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15. CS50 на русском: Лекция #15 [Гарвард, Основы программирования, осень 2015 год]

15. CS50 на русском: Лекция #15 [Гарвард, Основы программирования, осень 2015 год]

Channel: JavaRush

сomputer science

основы программирования

cs50

cs50 на русском

cs50 javarush

18 лекция cs50

гарвардский курс

Week 9

00:00:00

here's a site with shawarma works

00:00:04

[music]

00:00:16

welcome to harvard for the c course with

00:00:20

fifty

00:00:23

it's now fifty the beginning of the ninth week and

00:00:25

today is george boole's 200th birthday

00:00:28

we've referred to it multiple times when

00:00:30

using boolean variables and

00:00:32

true false and gender 10 and the like

00:00:35

today would have turned 200 and google

00:00:38

gives him credit if you want to

00:00:40

join lunch with the team with fichte

00:00:42

link on the course website these guys

00:00:45

are waiting for you here in cambridge and these are in

00:00:47

new haven and for the way ken in them or

00:00:49

didn’t make the so called gif and linea

00:00:52

recent

00:00:53

flexible meeting is a format of

00:00:54

graphic files familiar to you, it looks like something like

00:00:56

that, just a sequence of

00:00:59

essence, oh well, I’m not funny to you in the sniff,

00:01:03

we didn’t have fun, in general,

00:01:05

join here at Harvard on this

00:01:08

Wednesday for freshmen,

00:01:10

second and even third year students and who

00:01:13

want go to the computer tax class

00:01:15

there will be a consultation this Wednesday immediately

00:01:17

after class at four o'clock in the

00:01:19

computer science building Maxwell Dvorkin and

00:01:21

signed up tomorrow this information will also

00:01:24

appear on the site they say there

00:01:26

will be donuts for snacks okay funny story

00:01:30

I was poking around on the Internet and found the

00:01:33

archives of my old one site May

00:01:35

it turned out to be very timely because

00:01:37

again the election race of the

00:01:39

student council was on us in the street, in general, I then

00:01:43

participated in the elections and will continue partly, that’s probably why

00:01:45

my site looked like that then for some reason it

00:01:48

seemed interesting to me

00:01:50

before explaining to the people the essence of my

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platform the reason to vote for me

00:01:53

forcing them to click to log in and

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get information, looking back, I

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understand that the idea was stupid, you’re flying, I do

00:02:01

n’t know why I did it,

00:02:04

of course, it didn’t help my company

00:02:06

even by the last year, I realized I

00:02:09

had a calendar with the Muppets back then, the Muppets

00:02:12

were in fashion and maybe not, but

00:02:13

then I had a calendar with layouts and I decided

00:02:15

that it would be cool to name my Harvard network computer

00:02:17

fragman. student Harvard

00:02:21

the idea at that time we all had

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unique host names and we could

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choose a new,

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more sonorous name for myself, for some reason I chose

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the flagship, in general, I did

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n’t take a lot of time spent on these links

00:02:33

this morning, here’s the page for myself now

00:02:36

it seems lovely, but also according to it you can see

00:02:38

how far the progress has gone, I mean

00:02:41

that 486 was a thing today, it’s

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very, very weak, we

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probably have things in our pockets that are

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more powerful, there are other reasons for this,

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so I’ll just leave this here,

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but this was my first foray into the network, but

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no not my first first excursion into

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web programming, this site I

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forgot about it, I learned how to rivet

00:03:04

repeating pictures then

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this tile seemed impressive to me

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hockey players football and golf balls and

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what else for a sports site, in

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fact this was the first web project

00:03:15

that I mastered it maybe in the second or

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third year after graduating from ses Fichte disappeared

00:03:20

fifty van one of the next classes for us

00:03:23

looking through the archives I discovered that my

00:03:25

friend and follower had

00:03:27

rewritten the copyright to himself but

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I should still be ashamed,

00:03:30

however then as I said a couple of weeks

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ago it was the first site for registering

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newcomers, your sports section of the university, in

00:03:38

general, it turned out that having such background

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pictures was not the best idea on the web,

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it was a new thing

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and we were all experimenting, and that’s exactly what

00:03:46

I was doing then,

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okay, without further delay,

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let’s move on to the last topic, which will be

00:03:51

especially useful for you graduation

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projects and thanks to which the World Wide

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Web will become more understandable tired of

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being, we get acquainted with another

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programming language called java

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script, which is similar to the previously

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discussed languages, but not exactly like a

00:04:04

baby, we remember and the compiled language

00:04:07

is run through the compiler, it

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converts the source code into object code, that

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is, units and zeros and ones and zeros

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that understand your cp, aka the

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central processor php, on the contrary, is not

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compiled and what is the interpreted

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language the

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program interpreter reads it

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from top to bottom from left to right and calculates

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what your syntax means and should do

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if there is a conditional loop or some other

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program for the manual here what is an interpreted

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language there is nothing there we studied html

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html is not even a programming language as they would

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call mine a

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markup language this fancy term

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means that there are no programming

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constructs even like those we saw

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meetings there

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are no loops there are no conditions this language can

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only arrange data format

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them and how - then streamline

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disappeared with also not a programming language; it

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serves even more aesthetics; it allows

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fine-tuning of

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font size, color, and relative

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position; then there was a sequel; a sequel, after all, a

00:05:05

kind of

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programming language, although tailored

00:05:08

specifically for a database, we studied

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only the operations of selecting, inserting, deleting,

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changes and a couple more, but even they

00:05:15

allow you to write the so-

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called functions and procedures that are

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similar to the functions of php and sie ins,

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remember that they exist because we won’t

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bother with them, that’s enough for now

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and in general, you see the acquaintances and here’s the

00:05:29

latest java-script of the languages with

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which we will get acquainted java-script who is

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already an interpreted language who is in the subject

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tell me what features distinguish it from and

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stove what is the difference I did

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n’t hear it is not compiled, that is, it is

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interpreted they are compiled,

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which means it is similar to the Pirlo kitsch stove and

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yet it is strikingly differs from the stove

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at least in terms of using the new product,

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yes it usually works on the client, that’s the

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distinguishing feature for us at this

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stage, everything worked on the server in the sense

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that we did everything with a recess of fifty

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thousand and until now it also worked on the

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server because it interpreted,

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not compiled, but interpreted in the

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ses editor, which is a

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server or a group of servers in the cloud,

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why is it a java script, even if you start

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writing in it as part of the 8th medical problem book,

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and maybe you

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will write final projects in the ses fifty editor and

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save files in it

00:06:24

but it is not a cloud server and where it is

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located will not interpret and

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execute your code; instead, it

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will be transferred unchanged to the browser

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and Explorer or Chrome or Firefox

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or Safari or something else will interpret

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it from top to left to right the whole Andy is so key

00:06:43

The difference today is that java script

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on the client is a pretty penny, for example on the server,

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and there is also a catch from the point of view of

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intellectual property in

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who can see your code. Indeed, you

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can go to the Internet and find almost

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any code written in java script,

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sometimes it is legible sometimes it’s worn out, we

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’ll come back to this later, in general, the syntax of

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java script, to our delight, is all similar to

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C and like a stove there is no main function in it

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you want to write code in java script

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today you’ll learn how easy it is to get started, we

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’ll see that it’s especially good for

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web browsers small correction for

00:07:23

today, now you

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can increasingly use java script on the

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server using a sophisticated platform, but

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this is how some applications with

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fifty-fifty are written are written, but in

00:07:35

our course we will study javascript on the

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client side, this is how

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the conditions on the stove are written, excuse me although this is

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also correct, they also look like a

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java script in terms of syntax, it is identical to c

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and php, the

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Boolean expression is syntactically the same,

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all the shoulder stoves and

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java-script switch statements are the same here we have

00:07:58

similar loops for a while and duvall

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and here are the differences in the stove there was a construction

00:08:04

for each, perhaps you came across it in the

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orgy of the seventh java script problem books, there is

00:08:09

also a special version of it literally for work in

00:08:12

reality in firing travel, which in short I

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mean when I have an object for them

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and we’ll come back soon and I want to go through

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all its pairs key-value I don’t

00:08:24

need to come up with digital indexing for them

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0

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123 I can say this directly and for

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each iteration the java script instead of me

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assigns numbers to the keys in order

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first next and so on and I can

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get to its value of the java

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script work with an object width you’ll see as with an

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associative array with a php

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stove and so, if you finally

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figured out what the

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associative array of a

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stove is, you can still assume that a

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java script object is the same thing, although not everything is

00:08:54

so simple, the arrays here are very similar to a

00:08:58

stove,

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but without one sign there is no there is enough of

00:09:02

something that was in the oven last week and there is

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not a dollar sign, which means we are

00:09:08

back in the ordinary world where variables are

00:09:10

devoid of banknotes, but usually

00:09:12

they are preceded by a var var you reblog means

00:09:15

a variable and also in the oven there is weak

00:09:17

typing, that is, the data type is

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integers floating point numbers strings and

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so on java-script they also have its

00:09:25

weak typing is that

00:09:27

we programmers do not need to clarify

00:09:29

enough to know that these types are ips

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existential, therefore a variable like this we

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can declare string hello world

00:09:37

pay attention to everything as in stove but without a

00:09:39

dollar we will meet with this more than once

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today here is an object with keys and

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values as you noticed compared

00:09:46

to last week the syntax is a little

00:09:47

different take a closer look am how many keys does

00:09:50

this object have you think 4 and in your opinion two are

00:09:57

actually 2 a

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set of two key-value pairs key

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called symbol its value fb

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key called price its value 100

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153

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and that two key-value pairs remember the

00:10:10

stoves again small differences in syntax

00:10:12

nothing particularly smart interesting in the stove the

00:10:15

same thing would look like this

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quote equals this and changing to

00:10:19

square brackets to another then I

00:10:22

change this to the word price in quotation marks and also

00:10:25

remove: what I used last

00:10:28

week before equal and more conditional

00:10:31

arrow to the same thing here and the same

00:10:35

thing here that’s all if it’s not

00:10:38

in my memory yet nothing

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scary because it’s really

00:10:41

not interesting, it’s just differences in

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syntax, the essence is completely, even inside the

00:10:46

java script quotes variable

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there is a collection of key-value pairs,

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one of which is symbol and 2 price

00:10:53

to get to these values

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we use this syntax and like in the

00:10:57

oven I could would

00:10:58

like let's increase this a little oh hour

00:11:02

like from the stove I could without a damn but just

00:11:09

like in the stove

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okay we'll use notes like in

00:11:14

pete's stove you can enter the dollar

00:11:16

quote symbol and get the value of the

00:11:18

variable symbol and java script everything is

00:11:21

similar I can do it’s so easy to

00:11:24

remove the dollar sign, so we’re lucky, there’s

00:11:27

very little new syntax, let

00:11:28

’s focus today on some

00:11:31

ideas and applications, the first

00:11:33

application you’ve already seen is written if

00:11:35

you looked at the 7 problem book, it looks

00:11:37

like this, this problem book, even if you

00:11:39

haven’t opened it yet, contains a config file.

00:11:42

Jason that is, java-script object

00:11:45

Natasha's object annotation at mother-in-law's why

00:11:49

we decided to provide you with a sample in

00:11:51

key-value pairs

00:11:53

and here in the list the tail and server name are indicated

00:11:55

and a placeholder is also provided

00:11:57

for both your

00:11:59

username and your password

00:12:01

if you haven’t seen this yet don’t worry,

00:12:03

there is still a manual for the seventh

00:12:05

problem book; of course, you will need to

00:12:06

replace the work,

00:12:07

because at the entrance to the editor, the lucky one

00:12:09

each has his own login and password; we could

00:12:11

use here more than half a dozen

00:12:13

other formats; we could use

00:12:15

the file. text or with vip-file

00:12:17

or for example a.n. ai file xml file and

00:12:21

a bunch of other abbreviations that you haven’t even

00:12:23

heard of by and large this is a random

00:12:25

choice but the text format is especially popular today

00:12:27

Jason

00:12:29

java-script firing Nataysha this is it

00:12:32

he looks unclear but look at the

00:12:34

patterns at the beginning the opening curly

00:12:36

brace at the end the closing inside there is

00:12:38

some content of a

00:12:40

key-value pair, that is, now we

00:12:42

see on the screen an object that has one

00:12:45

key and one value, if we proceed from the

00:12:47

already familiar templates where the key is the

00:12:49

database, that is, what is to the left of :

00:12:53

it turns out that this time the value is

00:12:56

several the lines for the purpose

00:12:58

begin and end with a curly

00:12:59

brace, what type do you think the

00:13:01

value of the database is a dictionary or, more simply

00:13:07

put, an object is a data type

00:13:09

that can

00:13:10

contain other types within itself, and so

00:13:13

if this is all called an object and an object

00:13:15

means a set of key-value pairs that

00:13:17

value database is an object

00:13:20

value database is a whole bunch of

00:13:22

key-value pairs the first of them is host

00:13:24

then name then username password

00:13:27

each of these values is nothing more than a

00:13:29

string in double quotes if everything is still

00:13:32

not completely clear but remember that this is

00:13:34

just a boring template a method of

00:13:36

standardized storage of information,

00:13:37

but you can often make mistakes in

00:13:40

small things even in the seventh problem book if, for

00:13:42

example, you accidentally skip here, and the

00:13:45

model will lead to the fact that the file

00:13:46

most likely will not run and if you

00:13:48

accidentally miss the quotes it

00:13:50

will not run so the format is quite

00:13:51

capricious but very common and you

00:13:54

will use it even if in general

00:13:56

java script is not used in the seventh

00:13:58

problem book, remember this diagram in

00:14:02

html well, we said the code may look like this,

00:14:05

it’s just a hallow hunger to catch

00:14:06

written in markup language would be there,

00:14:09

but then we decided that we can

00:14:10

consider it like a tree,

00:14:12

the structure on the left, which we

00:14:14

formatted for ease of perception,

00:14:16

can be represented in the form of such a

00:14:18

tree; your special root element,

00:14:21

which we will call in the general word document,

00:14:23

underneath it is the root html element, or because.

00:14:26

html

00:14:27

which has two child elements, a

00:14:29

header and a body, in which the header has a

00:14:32

title, the title has a text value and the

00:14:34

body also has a text value,

00:14:38

if it’s more convenient for you, you can

00:14:41

draw such a diagram under this html code, this is a great

00:14:44

idea, a different model

00:14:45

because now that we have a java

00:14:47

script a programming language that

00:14:49

the browser can execute

00:14:51

and interpret for you, it

00:14:52

turns out that through code we

00:14:55

can start managing this

00:14:56

data tree in memory, personally, I need to build a

00:14:59

tree in memory, we don’t need to create

00:15:01

complex data structures like in the fifth

00:15:03

problem book, the browser loves to

00:15:05

interpret html from top to bottom from left

00:15:07

to right and without any extra effort on our

00:15:09

part, it gives us a kind of pointer

00:15:11

to this tree, it does all the dirty

00:15:13

work, that's how it takes care of mozilla

00:15:16

apple and others with the help of a java script, we

00:15:20

will be able to manage changes and do many other

00:15:23

interesting things with this tree,

00:15:25

also known as the house object model

00:15:28

document

00:15:29

what exactly to do, it turns out that the java

00:15:32

script has a long list of possible

00:15:34

events in the hotel, we didn’t remember this

00:15:36

term from week zero from problem book 0

00:15:39

when we talked about scratch, probably

00:15:42

few of you used the event in the

00:15:44

scratch project my way, but maybe you

00:15:46

remember a simple example with Marco Polo where

00:15:48

there were two sprites, one of which was

00:15:51

Mark, who spoke, and the second, having heard this event,

00:15:53

responded to Paul, if you don’t remember the recordings will help you,

00:15:56

but this is just a way of saying, and the essence of these

00:15:59

listeners is clear from their name. java

00:16:01

script gives us a way to

00:16:03

listen to how the mouse moves down or

00:16:05

up again. a key is pressed, a

00:16:08

key is released, how the form is submitted,

00:16:10

selection and resizing occurs,

00:16:12

otherwise they say for any action

00:16:14

that the user can perform and

00:16:16

does every day,

00:16:18

there is a code in the browser that will track it

00:16:21

and react in a certain way to the crowd,

00:16:23

for example, you use google maps,

00:16:25

what will happen if you click on the button and

00:16:27

drag click and drag with the mouse and you

00:16:34

map to a point on the map will begin to move and

00:16:37

you can look at

00:16:38

what is here and what is there and how Google

00:16:41

implemented it. I assume that they

00:16:43

use a couple of event listeners,

00:16:45

one of which monitors the mouse click

00:16:47

when the user needs a

00:16:48

treatise or a mouse button and then we

00:16:50

begin to monitor something like

00:16:52

movement or another event that

00:16:54

conveys to us movement movement,

00:16:56

by the way, also got into this long list of

00:16:59

possible options, it turns out this is a powerful

00:17:01

mechanism for responding to

00:17:02

user actions even before he or she

00:17:05

clicks something obvious like

00:17:07

confirm we will have to go through a couple more

00:17:09

topics to figure this out but for now

00:17:12

let's move on to the actual code

00:17:13

open to 0 this is a very simple example let's

00:17:18

zoom in to see the

00:17:19

elements and I'll type my name David and

00:17:23

5 help I'll click confirm and here a

00:17:26

clumsy popup window pops up

00:17:29

that says hi , David

00:17:31

this like that hello world that we

00:17:33

used to write taxis and even on the stove

00:17:36

since I dynamically substituted my name, I

00:17:39

can substitute someone else’s name, I just change

00:17:41

the text to khan and click confirm and the

00:17:43

window changes pop-ups on the

00:17:47

Internet they really abuse it because of

00:17:49

this in due time Blockers came into fashion

00:17:50

because certain

00:17:52

sites of probably dubious content

00:17:54

began to flood your screen with packs of

00:17:57

pop-up windows. In general, this ability

00:17:59

to put

00:18:00

windows in the foreground was not very

00:18:02

welcoming and was accepted by humanity, which is

00:18:04

why you see a warning here

00:18:06

that spoils the picture so much,

00:18:08

we’ll have to look for it to communicate with

00:18:09

the user there is another method, but for now it

00:18:11

will work anyway, the whole part is purely intuitive, that’s

00:18:14

what’s happening here and I click

00:18:18

confirm, it’s called some event, it’s obvious

00:18:20

what’s missing from the material

00:18:23

last week when I clicked

00:18:24

confirm what’s not on the screen again

00:18:30

reboot ural I haven’t changed he said

00:18:33

that they were loading the house, but it was still a

00:18:35

house, but actually we had to go

00:18:38

to a different url address, but something like

00:18:39

a register. stoves,

00:18:41

but even if I close the window by clicking ok,

00:18:44

look and rl remains, but let's say if

00:18:47

I doubt that I can open chrome,

00:18:49

I open the network tab, we see it is empty,

00:18:52

I confirm to Maria, you see there is no

00:18:54

data transmission over the network, absolutely no

00:18:57

http, and so if we look at the source

00:19:00

code let me close this window and go

00:19:02

to the source,

00:19:03

it’s interesting, it looks like new tags have appeared here,

00:19:05

including violin, let’s

00:19:07

look in the ses fifty editor what I

00:19:09

sent to the user, here it is, look

00:19:12

only at the html mud of the moon, this is the second

00:19:14

half of the file house 0. html you see

00:19:18

the title here so at least so body so forms so the

00:19:21

differences are immediately obvious,

00:19:23

especially if you have not written in

00:19:25

java script before, scroll a little to the right

00:19:27

here so input and another input for

00:19:30

confirmation and also a little

00:19:33

unusual, but we met with this in

00:19:36

css what is absolutely new has changed, yes here he is the

00:19:40

view

00:19:42

after the demo yes great, then it’s not clear and

00:19:45

where it says submit, see what’s

00:19:48

next it’s called an attribute according to

00:19:51

html terminology its meaning this

00:19:54

line in quotes at first glance

00:19:56

looks strange it’s not html it’s not piss

00:19:59

then how you guessed it, the sting of the script

00:20:01

seems to be that the web page has a built-in function

00:20:03

called grid greeting I come

00:20:05

to this conclusion because after the word

00:20:07

grid there are parentheses and ; everything looks like a

00:20:10

function and a function in php, of course

00:20:13

this is a java-script function, it returns

00:20:15

false, we will return to this now, but where is

00:20:17

the definition of the function, let’s scroll to the top of

00:20:19

the file, this line despite the

00:20:22

length without causing any difficulties, I’ll zoom out a little, pay

00:20:25

attention to these four lines java

00:20:27

script, like in a beer stove, literally

00:20:29

write the words function, give a name

00:20:31

because there are brackets with arguments, but in

00:20:33

this case, without arguments, java script,

00:20:36

like in a stove, there

00:20:37

is no return value, everything is not

00:20:39

as strict as

00:20:40

we open and close curly braces

00:20:42

java script has a built-in function not

00:20:45

recommended under the name and ice

00:20:47

which exists solely to

00:20:49

show the terrible pop-ups

00:20:51

that we have seen so far it’s all hard

00:20:53

to digest what’s going on here let’s

00:20:56

parse the string piece by piece oh like this is the

00:20:59

only arch

00:21:00

ment of the alert function and what it gives us is similar

00:21:03

to a regular string it turns out to be

00:21:06

unlike stoves and squeezing Oscar, sorry,

00:21:08

unlike php and at sea

00:21:10

java script, it doesn’t matter what to use

00:21:12

single or double quotes, the essence does not

00:21:14

change, to be honest,

00:21:16

java script programmers for some reason prefer

00:21:18

single quotes, a matter of taste, we could

00:21:20

instead put double Lewis quotes to the

00:21:22

block here lus is a new symbol for us,

00:21:24

who has encountered this before, what does

00:21:26

plus media and concatenation mean, we

00:21:32

saw this in the nickname

00:21:34

php operator. glues two lines together,

00:21:36

this is all a real pain in the sixth

00:21:38

problem book, remember it was Moroccan

00:21:40

construction, the functions of a line were combined

00:21:42

after allocating memory on the stack or on the

00:21:44

heap,

00:21:45

such dances with a tambourine just to

00:21:46

connect for a line in Omsk, everything is just

00:21:49

enough to put pluses between them for the

00:21:51

most difficult thing we have here here because

00:21:54

at the end of this line I just add !

00:21:57

so if we had people popping up in the windows and Lu

00:21:59

David Heal at Khan Solo Maria and the

00:22:02

like, it’s clear that this piece of

00:22:05

code between two pluses should give me

00:22:07

access to what’s asking here, well,

00:22:16

let’s pretend that I heard the answer the name

00:22:18

these names popped up in the window that’s all this

00:22:21

means, as I said when analyzing this

00:22:24

scheme, the so-called house has a special

00:22:27

root element at the very top, the moment they are

00:22:30

afraid of the documents,

00:22:32

now it turns out that this is a special

00:22:34

global java script variable in

00:22:36

which a lot of useful

00:22:38

functionality is hardwired days of useful functionality

00:22:41

includes the ability to access

00:22:43

any child node,

00:22:45

that is, all these squares and

00:22:47

rectangles and ellipses are those same

00:22:50

nodes, it turns out that in the

00:22:53

document object in java script there is a function

00:22:56

or, in other words, a method called get

00:22:59

element buy ID

00:23:01

for calling a java script function from an

00:23:03

object from

00:23:05

or a variable is used. we saw

00:23:09

lac all this syntax tract jussi seventh

00:23:12

problem books something similar with fifty : : : :

00:23:18

php one of the ways to call a function without

00:23:21

inside an object java script is coping with this so far

00:23:23

.

00:23:24

and this function, as it were, kindly tells

00:23:26

us what it does, produces an element by its

00:23:29

go one element is just an

00:23:31

alternative name of a tag or node in

00:23:33

the house, that’s all, get an element by

00:23:35

ID name means

00:23:37

here is my html based on this code which

00:23:41

node or html tag Ilya programmatically I'll get it

00:23:44

if I call the document.

00:23:48

get element your id yes, I’m sure

00:23:52

I’ll get the value from the element whose id

00:23:54

name is in quotes so in this case

00:23:56

it’s the get element b go function, as it were,

00:23:59

returns us a pointer to a specific

00:24:01

node in the tree

00:24:02

we didn’t draw the tree itself, but it’s the

00:24:04

same as getting this

00:24:06

rectangle or that rectangle

00:24:08

by accessing it by a unique

00:24:10

identifier what is the benefit of this it

00:24:13

turns out that when you reach

00:24:15

this node of this rectangle on the diagram

00:24:18

but it in turn gives you a whole

00:24:21

stack of data properties or

00:24:24

key-value pairs

00:24:25

one of the keys called target

00:24:27

value or it’s not easy to

00:24:29

explain this, but in the end the only

00:24:31

goal is to get a

00:24:34

string entered by

00:24:36

the user from this hierarchy, something I don’t like here,

00:24:39

or rather, some things still raise

00:24:41

questions, let’s say it all works, but

00:24:44

why do you think I’m returning false when

00:24:46

calling grid it looks weird

00:24:49

because there are two expressions separated by

00:24:50

semicolons guess

00:24:53

if I remove the return value what

00:24:56

will happen what do you think dough instincts play

00:24:59

you could repeat a

00:25:02

bunch of windows will open perhaps something could

00:25:05

happen and what else should I

00:25:07

send the request to to the same page

00:25:12

to the same page is already closer to the truth,

00:25:15

although unlike previous examples I did not

00:25:18

specify the action attribute, which is for

00:25:20

this dinner, but it turns out it is there by default

00:25:23

where specifying action is the same as

00:25:25

putting empty quotes or the name of the

00:25:28

file itself in this case home 0 . html this is

00:25:32

kind of implied what will happen

00:25:35

if I don’t do this I save it

00:25:37

here I removed it return false open the

00:25:39

example again and update it you probably

00:25:41

noticed I always advise roosting

00:25:44

fifty discos if something works crookedly

00:25:46

and the browser behaves strangely quite

00:25:48

simply hold shift and shout update

00:25:50

this will reload any file and without

00:25:52

using cached data or

00:25:54

copies from memory

00:25:55

and now I open one spectrum

00:25:59

network tab and check the save

00:26:02

log box because I don’t want the

00:26:03

lines to disappear as soon as I

00:26:05

go somewhere open in now I I’m typing here and do

00:26:08

n’t press confirm, perfect,

00:26:10

everything seems to be according to plan,

00:26:11

written by Holo Andy, I press ok, interesting,

00:26:14

look, the page has been updated, it’s back to

00:26:17

the home page, but the url has changed a little, and it

00:26:19

appears at the end? a standard sign

00:26:22

that we confirmed the data and below,

00:26:24

for greater clarity,

00:26:25

we see an http request and response with status

00:26:28

200 brought me back here,

00:26:30

but that’s not what we need, really, I don’t

00:26:32

want to reload the entire page, instead it’s

00:26:34

better to return false to shorten the

00:26:36

standard browser algorithm, the essence of

00:26:38

which is to reload

00:26:40

page,

00:26:42

I suggest you look at a more serious example,

00:26:44

this is a house version 1, look here, it’s not

00:26:48

scary if you don’t enter individual

00:26:51

lines of code, but what is the fundamental

00:26:53

difference between this implementation, we’ll agree that

00:26:56

it works the same way, the result doesn’t

00:26:58

change, what I did differently, the object

00:27:06

is placed inside the script, the function is defined before

00:27:17

is defined differently, in

00:27:19

other words, it is not in the form tag in the

00:27:22

seventh line, that is, in 8 there

00:27:25

is no longer the attribute it submits,

00:27:27

but in the previous example it was and then I

00:27:29

described the code right here at the end I said

00:27:32

it will return false and if that hasn’t confused you yet it

00:27:35

should also soon be like it was with

00:27:38

html

00:27:39

when we started combining it with s in the

00:27:42

style attributes, confusion immediately began

00:27:44

and doubts arose here, the same thing

00:27:47

if you write html code and then throw a

00:27:49

java script thread into it in the form of a string in

00:27:52

quotes, it will be difficult to maintain it, that’s how it

00:27:55

started In general, it’s not clear to do a

00:27:58

java script somewhere,

00:27:59

so from the point of view of good

00:28:00

design it would be nice to separate html and

00:28:03

java script to ride for this here we

00:28:05

did it like this, we used

00:28:07

html only for markup alma anthology

00:28:11

version 1 I only have this and forms with a

00:28:14

unique ID and here below I

00:28:17

used a special java

00:28:19

script functionality that gives me a so-called

00:28:21

anonymous function that turns out to be if I

00:28:24

call the document.

00:28:26

get element buy a and d for the house Nikita,

00:28:29

as it were, I’ll get a pointer to this

00:28:31

tree node on the so-called Tesla form,

00:28:34

let’s put it down, I know a little html or

00:28:36

I read on the net that the form element

00:28:38

is supported by a whole bunch of listeners,

00:28:40

in other words, an infinite list of

00:28:42

long, which we saw a little earlier

00:28:44

commander I know from reference books that he

00:28:46

himself does not have a suitable listener and hall for the

00:28:49

form element about Athos. If I know this, then I

00:28:54

can do this like this: take this

00:28:56

tree node of the form element and access

00:28:59

its property, it is jointly hit. it

00:29:02

just means that this property is like a

00:29:04

special value inside it

00:29:05

and what data type do I assign to the property

00:29:08

it submit which is actually a

00:29:10

variable in this tree node time tea

00:29:14

this is a field inside the structure what

00:29:18

data type it has before this function cf it turns out

00:29:21

there is such a thing in the oven and although we didn’t

00:29:24

everyone tell you that there are also pointers to

00:29:26

functions, that is, the ability to assign

00:29:28

functions as values of variables,

00:29:31

but we will not return to C for now

00:29:33

we will assume that here on the right, although it

00:29:36

sounds strange, they

00:29:37

say and took

00:29:39

give me a function, I won’t even

00:29:42

come up with a name for it because what I’m going to

00:29:44

attribute, let’s call it the address directly to

00:29:47

it’s submission, in other words, the browser, you

00:29:49

don’t need to remember how this function works,

00:29:52

you just need to know where it is

00:29:53

in memory, so you can put an

00:29:56

equal sign here and not bother with the

00:29:58

name of the types y or flu or something

00:30:01

else. here it’s just a question of design I

00:30:04

can move the curly brace excuse me

00:30:06

to the next line as usual all

00:30:09

swift but in java script they usually leave the

00:30:12

opening curly brace on the same

00:30:14

line

00:30:15

then nothing interesting the opening

00:30:18

curly brace just marks the beginning of the

00:30:19

function the function is the same only I

00:30:21

inserted return false inside the function

00:30:24

because it turns out that you can

00:30:26

only find out about this in reference books,

00:30:28

that if the function that you assign to

00:30:30

the handler, it sorbitol returns false,

00:30:33

the browser knows that there is no need to send

00:30:35

the form to the server, but if it returns

00:30:38

true, thin and send to exit and soon

00:30:41

we will figure out why I. a comma after the

00:30:43

second curly brace means I’ve finished

00:30:45

describing the function, it knows what to do as

00:30:47

soon as you get confirmation good

00:30:51

replay but it still looks clumsy

00:30:54

what else can we do it

00:30:56

turns out version 2 is the last one

00:30:58

let’s look at it am we risk ruining everything further

00:31:02

but it turns out there is such a

00:31:04

library as jack believe DJ to believe the

00:31:07

mega-popular java script library

00:31:09

so much so that many people generally

00:31:12

confuse jack believe java-script why the

00:31:14

java script itself is too

00:31:16

verbose my document.

00:31:18

get element buy ID blah blah blah blah blah

00:31:21

blah it turns out to be a very long code but an

00:31:24

eccentric named John Resik who now

00:31:26

works in one startup but created the

00:31:28

Jack Vere library quite a long time ago

00:31:30

by Ekimov and many have since contributed to it

00:31:34

so its syntax is a bit has changed

00:31:37

look here

00:31:38

you will definitely have to deal with this

00:31:40

if you take on the

00:31:42

final web project this is an alternative

00:31:45

way of writing functions too with the help of

00:31:47

this

00:31:48

swelling of water we won’t chew

00:31:50

each line just highlight a couple of

00:31:53

templates and how many anonymous functions or nameless functions are there in this code fragment

00:31:59

functions o

00:32:00

or lambda function 2 yes, this is clear even

00:32:05

if you are still swimming in the topic because the

00:32:07

word function with parentheses

00:32:08

occurs twice and so what does this code

00:32:10

do people and in the future we will also

00:32:13

call on the online reference book for help

00:32:15

now this simply means that when

00:32:17

the document is ready you need to register the

00:32:19

following function as a handler

00:32:20

it submits for html elements of the IDID and

00:32:24

when everything is done you need to call these two

00:32:27

lines of code and that, unfortunately, is an even

00:32:30

longer way to return false we

00:32:32

have we are talking about this because you

00:32:34

will see such code on the network and don’t be afraid of it,

00:32:36

just understand

00:32:38

that java-script is a common

00:32:40

paradigm, that’s why I’m showing it to you,

00:32:43

okay, let’s not dwell on this

00:32:45

syntax, do you have any questions

00:32:47

or thoughts about this example, okay,

00:32:52

let’s try to put it into

00:32:54

practice aubade throw it a web

00:32:56

page that just says hi

00:32:58

doesn’t cause anything interesting doesn’t strike the

00:33:00

imagination it won’t be much

00:33:02

prettier but at least useful let’s go back to the

00:33:05

folder and open say pin-up forms 0 .

00:33:08

html let this be a country with

00:33:11

registration in the sports section of the university

00:33:13

without any styles and design, I want to

00:33:15

register here, enter a password,

00:33:17

I’ll go straight to the conditions and click registration and

00:33:20

the site will say you are registered, but it doesn’t

00:33:22

quite seem to work, but

00:33:25

let me update

00:33:26

and now I’ll write no

00:33:29

you don’t need my real address, but I’ll just write here Malon,

00:33:33

let it be one two three 4 5 and now,

00:33:38

just because I’m a fool, I’m posting here one

00:33:41

two three 4 5 6 7 8 9 and I won’t put

00:33:43

a check mark like that, yes, there’s something to

00:33:47

work on here like you know or find out all the

00:33:49

God problem books you can write code and you

00:33:52

will have to write code in PHP protected from

00:33:55

such user errors because the

00:33:57

user is not always ready

00:33:58

to cooperate

00:33:59

he may not provide all the necessary

00:34:01

information or give it in the wrong format the

00:34:03

amount of these 7 problem books you will see that

00:34:06

you can set several conditions so that the

00:34:07

email address is in the style of

00:34:09

username doggy something. idea, and

00:34:12

if not, then you can apologize to the

00:34:14

user, as in the seventh problem book,

00:34:15

or if the box is not ticked, and

00:34:18

this can also be tracked, and of course, if they do

00:34:20

not match in role, as in the register.

00:34:22

oven in front of the father of the problem book and this can be

00:34:25

detected, but the ambush is that we need to

00:34:27

go all the way to the server to inform the user

00:34:29

about the error and if we don’t use a more

00:34:31

cunning technique, he will have to click on the

00:34:33

back arrow

00:34:34

no longer true, it would be better like on

00:34:36

modern sites so that the program

00:34:37

responds faster immediately, in other

00:34:40

words, let's move on to version 1, although

00:34:42

it will not be a move, that is, it is not better, but

00:34:45

at least it already has such

00:34:47

functionality million times two three 4 5 times two

00:34:50

three 4 5 6 7 8 9 I

00:34:51

don’t check the box registration password do not

00:34:53

match and although the pop-up window is crooked,

00:34:56

over time we will replace it with something like

00:34:58

bootstrap, and you will see in the seventh problem book

00:35:00

this is a popular library, we have already noticed

00:35:02

that the passwords do not match,

00:35:04

okay, I will correct it on behalf of the user,

00:35:06

say one two three 4 5 time two three 4 5

00:35:09

again I don’t accept conditions you must

00:35:12

accept the conditions of the thing with but why and puede

00:35:15

I have already stated that there is a way and we even

00:35:18

asked you in the seventh problem book

00:35:20

to detect such errors on the server side

00:35:22

so why should I do the same in

00:35:25

java-script here are the arguments in favor of the

00:35:28

fact that here you will see it will complicate everything even more

00:35:31

and maybe there aren’t any there

00:35:39

are options that may be

00:35:45

interesting a possible vulnerability of course

00:35:48

if you are not going to process

00:35:49

erroneous user data it may be

00:35:52

better so that they don’t get to your

00:35:54

server at all return everything back they say

00:35:56

fix the problems first

00:35:57

rightly more options not unlimited,

00:36:01

right, this code, as we have already said,

00:36:03

is interpreted on the client, it does not

00:36:05

reach the server and therefore does not affect the

00:36:07

load on the server capacity while we are

00:36:09

having fun here, this is not so important,

00:36:12

I only have one user here for now, but

00:36:14

if this is a decent-sized site or

00:36:16

one of the large ones like Facebook,

00:36:17

the more people you keep on the

00:36:19

server, the better because the server,

00:36:21

of course, has a limited supply of

00:36:23

RAM, a limited number of gigahertz, a

00:36:25

limited number of actions per

00:36:27

unit of time delta, so the more

00:36:29

people in the world who knock on your

00:36:32

server and have the wrong Latin alphabet, the better

00:36:34

the server will save you from this loading,

00:36:36

besides, especially for mobile devices,

00:36:38

if you log in to us May Harvard or

00:36:40

Yale there is no ID such sites load

00:36:42

late so it takes a

00:36:44

whole second or even 2 and then oh my God

00:36:47

if you misspelled you will have to

00:36:48

click back and that’s it at first, in general,

00:36:51

there will be a delay, especially if the

00:36:53

Internet connection is poor,

00:36:54

even if it’s a java script that

00:36:56

runs on the client and therefore shouldn’t

00:36:58

run back and forth when the connection is bad,

00:37:00

we get feedback almost

00:37:01

instantly

00:37:02

and now we go here, open form 0 and

00:37:05

look at the html and just Let's read that

00:37:09

here this is a form element whose action is equal to

00:37:12

resistor. stove

00:37:13

I use get to see believed but

00:37:15

for passwords we would of course change it

00:37:17

to fluorine and here is an input field of type text

00:37:20

another input field of type password and and here

00:37:23

you may not be familiar with an input field of

00:37:26

type checkbox but this is not java-script

00:37:28

it’s just html which opens the file

00:37:31

g-star. oven at the

00:37:32

obverse

00:37:33

one where the windows were popping up what's

00:37:35

going on there version 1 which I'll

00:37:38

open now I thought I had enough words but

00:37:42

it seems they've run out version 1 version

00:37:50

1 here it is

00:37:52

version 1 look here not the best

00:37:54

implementation but the very first one with the

00:37:57

form tag I have here like this the atek script

00:38:00

means the browser has a piece of code here,

00:38:02

usually in java script, and now look

00:38:04

what I’m doing in the line,

00:38:06

barely visible, do line 32 there is a

00:38:09

forms variable, give me the

00:38:12

forms variable and then call document. get

00:38:16

element buy go by id registration that's

00:38:19

where it's from let's scroll up

00:38:21

it turns out that I assigned the forms element a

00:38:23

controversial but meaningful identifier

00:38:25

registration so I get a variable

00:38:28

that will allow me to get this node

00:38:30

this rectangle from the tree

00:38:32

called form forms. he farms,

00:38:34

which means that the browser registers an

00:38:37

event listener for form elements,

00:38:38

in other words, when the form is confirmed,

00:38:41

execute the following code, he doesn’t need this name

00:38:43

because why do we need his name,

00:38:45

it’s enough to know what to do means

00:38:48

it’s anonymous or a lambda function and this

00:38:51

function is written on a few lines

00:38:53

below and now, to be honest, even if you have

00:38:55

never written code in java script

00:38:57

following the logic of this stove

00:38:59

if forms. and mail.ru equals equal empty

00:39:02

quotes, that is, if the email field is empty,

00:39:04

we scold the user, fill in more

00:39:07

addresses, otherwise if the forms . password. in

00:39:10

Ilya empty again we scold the user,

00:39:12

fill in more than the password Mountie

00:39:15

becomes much more interesting in a number of forms.

00:39:16

passport . value is

00:39:18

not equal to forms. confirmation. value y and

00:39:21

where did confirmation white come from we turn

00:39:23

up so I called this input field

00:39:26

password

00:39:27

and here I called this kanfer smaller I

00:39:29

could call it sent it

00:39:31

or anything from just checking the logic

00:39:33

so that they match otherwise again

00:39:35

we turn to Mr. broth logical

00:39:37

value check boxes

00:39:38

so if ! that is, if not

00:39:42

forms. and hryvnia. the effect is again a reprimand

00:39:45

to the user, as you will see, this

00:39:48

syntax is widely used in

00:39:49

java-script, this form of recording is via .

00:39:51

first there is an object then it means and

00:39:53

properties for example password before then the

00:39:56

actual value

00:39:57

look again here is the input field here is its

00:40:00

name password

00:40:01

and its value is whatever the

00:40:03

user enters in all these cases I

00:40:05

returned false otherwise I return

00:40:07

true here it is by force when you

00:40:10

return false to interrupt the

00:40:12

user's action and force him to select or

00:40:14

type again otherwise

00:40:17

return

00:40:18

true I'll show you another version

00:40:21

of this task just so you can get a better understanding

00:40:23

version 2 all in forum 2

00:40:27

perform with a slight movement of the hand this is

00:40:30

for the curious version on Jake Vere

00:40:33

you might want let's dig into this

00:40:35

library let's get started ok now

00:40:37

they don't have any questions I'll slow down for a

00:40:40

second because we drove for a long time and

00:40:42

quickly it's good that all this code is

00:40:45

more or less the same

00:40:47

from new material what is about what

00:40:48

are rectangles what is a class you

00:40:50

what is an anonymous function what is an

00:40:52

event handler however most of it

00:40:54

fortunately repeats itself from week zero

00:40:57

okay let's move on to the interesting part

00:40:59

first let's open google maps

00:41:01

google maps

00:41:02

pay attention for a moment for a split

00:41:05

second

00:41:06

look what happens if I click

00:41:08

quickly spin-off no connection at

00:41:10

Harvard it’s so fast that you ca

00:41:12

n’t even see it, but what should you see if I

00:41:15

click and drag very quickly who is

00:41:18

watching us online if you

00:41:20

double the speed you’ll see

00:41:22

better what happened before I clicked and dragged

00:41:25

let’s do this in a different way for example

00:41:29

90210

00:41:30

was heading away from no too

00:41:32

quickly again what about disney world but here

00:41:36

it is yeah what did you see for a split second

00:41:39

something like squares to the placeholder and

00:41:41

instead of tiles what was it Google Maps a

00:41:43

great example of a technology called

00:41:44

Weeks and this is where using a java script

00:41:47

becomes especially tempting there

00:41:49

used to be a site called metk weight you had to

00:41:52

take a screenshot back in the

00:41:53

nineties there if you needed to

00:41:55

look at the map above you had to

00:41:57

click on the up arrow which led to the

00:41:59

next square of the map if you

00:42:01

needed to move it to the left you had to again

00:42:03

click on the arrow move to another

00:42:04

square of the map some sites still

00:42:07

work like this, well no the quest

00:42:08

has been corrected like google maps and google but

00:42:10

instead today many sites

00:42:12

use

00:42:13

oh ok oh ax also known as

00:42:15

asynchronous script java script or xml

00:42:18

it's just a complicated name technology

00:42:21

or technique that allows the browser,

00:42:23

using a java script, to make

00:42:25

additional http requests after the

00:42:27

page is loaded

00:42:28

and part of the bin but what does this mean but you would be

00:42:31

tired if the dml every time you

00:42:33

need to check after required you to press

00:42:35

control r or commander or the

00:42:37

refresh button so that the whole the damn page

00:42:38

was overloaded though it was restored

00:42:41

white for a second you looked at the

00:42:42

stupid loading indicator to

00:42:44

see if you had a new letter the

00:42:46

whole page and the legal address would have to be

00:42:48

reloaded to jmail it works somehow

00:42:50

differently so when you receive a new

00:42:52

letter you pressed how the screen behaves

00:42:54

it just appears at the top yes it

00:42:56

magically appears as the top

00:42:58

line in the list in fact it's all

00:43:00

quite complicated really if you

00:43:01

think about this tree although it's

00:43:03

simple and jmail you'd have to look

00:43:06

at the code to make sure of this they're most

00:43:08

likely using an html table or a

00:43:11

bulleted list in the form of which it

00:43:12

displays a message in the inbox, if you

00:43:14

imagine that this is a memory tree, then when

00:43:17

using GI mail something like this happens when

00:43:20

google understands oh you have a new message

00:43:22

admin, but it will not

00:43:24

rebuild the entire tree; rather, it will

00:43:27

find a tree node that is different from the

00:43:29

inbox and just paste a new node

00:43:31

is similar to the task from the 5th problem book where you

00:43:34

inserted nodes in the vtap hash table,

00:43:36

and google its code java script

00:43:39

scans the tree, finds out where the part of

00:43:42

the window is responsible for the incoming ones and

00:43:43

inserts a new line, a

00:43:45

new line is just one or

00:43:47

more new nodes in the tree in general

00:43:49

Ajax a special technique created

00:43:52

specifically for this when visiting a url, no matter how

00:43:55

long it takes to load after the

00:43:58

page has fully loaded,

00:43:59

but you can still pull up new

00:44:01

data from the Internet, be it messages

00:44:02

or map tiles, take them out of the bins

00:44:05

and insert the page so that the

00:44:07

user does not have to wait, also

00:44:09

works messenger Facebook any

00:44:11

sites could become and even so I want to

00:44:14

say that it’s terribly annoying

00:44:15

lately if I start looking for

00:44:17

cats from the user’s point of view it’s

00:44:19

a nightmare it offers options instead of

00:44:21

me everything it does and the url has not changed

00:44:24

since I started typing text but

00:44:25

what's happening with the network

00:44:27

I'm doing interesting what's happening with the

00:44:30

network bright and even stranger okay

00:44:34

let's look at the code of the element and for

00:44:37

this we go to the network tab and try to

00:44:39

explain everything scientifically without cats and

00:44:41

while I'm typing verbatim cats and that's what's

00:44:46

happening I

00:44:49

won't I click here okay, it means

00:44:53

here below what we see after each

00:44:55

character that I enter 1 lower level

00:44:59

what happens after each character

00:45:00

entered from the keyboard yes exactly the characters

00:45:05

get into google one by one on

00:45:07

their server they build a string that

00:45:09

represents everything that I have already typed

00:45:11

and Every time I add a sign, they

00:45:13

mix up their secret

00:45:15

search algorithm and guess this or not this

00:45:17

page with cats, I

00:45:19

mean to them, in a sense, it makes my

00:45:21

life easier because I don’t even need to

00:45:23

finish my thought threads; of course,

00:45:25

autocomplete is a useful thing, in principle,

00:45:27

if their algorithms are good enough and

00:45:29

if my queries are obvious enough I

00:45:32

don't need to write down the words they

00:45:33

will tell me what I want to find so

00:45:35

instant google search is just an

00:45:37

ajax technique using code that

00:45:40

allows you to

00:45:41

request additional content through the

00:45:43

browser behind the scenes using this new

00:45:45

java script language.

00:45:47

so we still have a couple of minutes left,

00:45:49

let's call my friend Colton Auto on stage since the

00:45:53

presentation of the kalyk technology that you

00:45:56

showed interest in your final

00:45:57

projects was a lot of fun, although we decided that we could

00:45:59

use volunteers to

00:46:00

demonstrate to you an addition

00:46:02

that will allow you to see this hand

00:46:04

first come here, very cool, well done,

00:46:07

now we'll connect this to the monitor,

00:46:09

describe your name so everyone knows me

00:46:12

and fa fa fa fa fa fa, nice

00:46:14

to meet you, okay, let's get everything

00:46:16

ready, come out here in the middle

00:46:18

with the cardboard in Colton's hands, the

00:46:20

control panel and instead of standing in

00:46:22

this three-dimensional world, looking

00:46:23

around like Colton last time,

00:46:25

today he will walk forward back

00:46:27

left and right like a Nintendo or

00:46:29

x-box joystick,

00:46:31

I was standing somewhere here, but everything is possible,

00:46:34

give it as a gift, okay, putting this thing on,

00:46:38

let me switch the picture to the monitor and

00:46:43

when we turn off the light from Inna Colton, I’ll stand

00:46:46

here next to you, you’ll tell me, but the microphone

00:46:48

what’s happening in the do it, of course,

00:46:51

we’re now loading the Oculus Operative, not the

00:46:54

operating system, but the main program

00:46:56

from which you have access to all the games and

00:46:59

applications in your collection, now she’ll

00:47:02

say tap touchpad to start

00:47:04

dochp this is located on the right side of the headset,

00:47:07

you can press one on it and there you go,

00:47:13

it sees everything in much better quality,

00:47:16

but the picture is on Wi-Fi, now you

00:47:18

need to look at the top right corner of

00:47:20

the screen, yes, this game is at the very top

00:47:23

right when you select it again press

00:47:26

on the touchpad it looks like this duet is halls

00:47:29

and now it appears

00:47:33

let me hold your glasses for now and so I

00:47:38

gave him the headset he can control the

00:47:41

game he

00:47:42

can move in space and all

00:47:44

that look up it

00:47:45

says new game forward let

00:47:48

's start now you can control

00:47:50

yourself using the headset

00:47:52

like As soon as the game loads, it might

00:47:58

be scary, it’s time to say about

00:48:02

it, okay, I’ll check if you can

00:48:05

move, it turns out great,

00:48:08

look down you have a map on the map, you

00:48:10

can see where you are, you can look around

00:48:13

the room,

00:48:14

you can turn around completely like this,

00:48:16

turn around, look to the left, I think there’s

00:48:21

something on the barrel what you can

00:48:22

pick up or how to remove the map from the road

00:48:25

look above

00:48:26

just raise your head like this,

00:48:28

go forward and turn around look even

00:48:35

further to the left look left continue left like this and

00:48:41

go to it using your headset

00:48:46

like this now a hint will appear

00:48:48

pick up here it is pick up the bottle come on

00:48:51

to get out of this

00:48:53

edict room and the door now you need to press

00:48:57

there there is a hint to

00:48:58

press the button so that it opens

00:49:00

let's press the button here it

00:49:03

opens well done and so we

00:49:06

leave the room further let's think for

00:49:11

ourselves and

00:49:12

see what else you find and I don't want to go

00:49:19

into this dark room and stop, how can I

00:49:22

get through the dark hall

00:49:23

no, it’s better to go back everything is fine there are

00:49:31

still useful items there, pick up it looks like it’s on a

00:49:34

coin and this is a master key

00:49:35

if you find a locked door you can

00:49:38

use it scary for now okay

00:49:47

pretend until you

00:49:48

get into the role as if you’re standing there and if

00:49:51

you turn to you need to get used to this but

00:49:54

everything is logical and for now it can go

00:49:56

on for the whole day, I suggest

00:49:58

you sneak out of here but we

00:50:00

have two more couples if you want to go

00:50:02

play, the rest of us will see you next

00:50:04

Wednesday and thank you for the volunteer day

00:50:06

translated and voiced by the studio up

00:50:10

diver by order java rush

00:50:13

[music]

00:50:16

I'm fixing the TPL bayonet, I

00:50:19

've already changed the low-pass filters, what are you doing,

00:50:21

well, look at each of them, I'll show you, for

00:50:25

example, this one, you

00:50:26

see here, in my opinion, I'm full, if you

00:50:28

want more, no thanks, okay, help yourself to a

00:50:38

different color, in fact, this thing

00:50:41

adjusts the colors

00:50:44

translated and voiced by up diver studio

Description:

Доп. материалы и задачи к лекции - https://javarush.com/quests/lectures?quest=QUEST_HARVARD_CS50&level=9 Весь курс CS50 - https://javarush.com/quests/QUEST_HARVARD_CS50 CS50, или Computer Science 50 — это курс Гарвардского университета, посвящённый основам программирования. Тема восемнадцатой серии цикла — введение в ДжаваСкрипт и программирование на стороне клиента. Впервые в истории студенты двух учебных заведений — Гарварда и Йеля — при помощи современных технологий параллельно проходят обучение на курсе.

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