vscode & JavaScript

# Web Site Writing Basics

# javascript # vscode

Writing JavaScript (JS) for beginners can be done simply without needing to install any of the many programs at first. It can be started in the most basic way, using browsers and HTML files.

1.Initial JavaScript writing method

1.1 Writing in the browser (Console)

It is the simplest and quickest way to experiment with short coding:

1.Open a web browser (such as Chrome, Firefox).

2. Right-click any web page and select "Inspect" or "Developer Tools" (Developer Tools).

3. Go to the "Console" tab.

4. You can type JavaScript commands into it. For example:

❇ Type alert ("Hello World!"); and then press Enter, an alert window will appear.

❇ Type console.log ("This is the text in the console"); and then press Enter. The text will be displayed in the console.

1.2 Writing in HTML files (for websites)

Because JavaScript is primarily designed for use in browsers, combining code with HTML is the most popular way:

1.Create an HTML file: Create a new file in a text editor (such as VS Code, Notepad) and save it as a name, such as index.

2.Add the < script > tag: Insert your JavaScript code within the < script > tag in the HTML file:

HTML

< html >

< head >

< title > My First JS < / title >

< / head >

< body >

< h1 > Try writing JavaScript < / h1 >

< script >

/ / This is JavaScript writing.

/ / Text display in console

console.log ("JavaScript code is working!");

/ / Order to change the content of the h1 tag.

document.querySelector ('h1') .innerText = 'JavaScript has changed text!';

< / script >

< / body >

< / html >

3.Open File: Open index.html file with web browser (double click).

1.3 JavaScript file separation

For more complex projects, JavaScript code should be separated into separate files:

1.Create a JS file: Create a new file and save it as a name, such as app.js.

2. Write code in the app.js file:

JavaScript

/ / app.js

console.log ("Code from the app.js file is working!");

alert ("Hello!");

3.Link in an HTML file: Use the src attribute in the < script > tag to link to the app.js file:

HTML

< html >

< head >

< title > External JS < / title >

< / head >

< body >

< h1 > External file link < / h1 >

< script src = "app.js" > < / script >

< / body >

< / html >

2. Important basics to know

Concept, Brief Description, Code Sample

Variables (Variables) are used to store data. There are main keys: var, let, and const let name = "Alice"; const PI = 3.14;

Data type (Data Types) JavaScript contains data types such as string (text), number (number), boolean (true / false), object (object), array (sequence row) let age = 30; let isStudent = true;

Functions A group of commands that perform specific functions for reuse. Function greet (name) {return "Hello," + name;}

Conditions (Conditions) Decisions to run a program, such as if, other if, other if (age > = 18) {console.log ("Adult");}

Loops (Loops) Repeating the original set of instructions multiple times, such as for, while for (let i = 0; i < 5; i + +) {console.log (i);}