JavaScript Syntax

JavaScript 语法基础

JavaScript 是一种广泛使用的编程语言，它主要用于网页开发。以下是一些基础的 JavaScript 语法要点。

变量声明

在 JavaScript 中，有几种方式可以声明变量：

使用 var 关键字
使用 let 关键字
使用 const 关键字

var a = 10;
let b = 20;
const c = 30;

数据类型

JavaScript 有以下几种基本数据类型：

number：数字
string：字符串
boolean：布尔值
null：空值
undefined：未定义
object：对象

let x = 5; // number
let y = "Hello"; // string
let z = true; // boolean

运算符

JavaScript 支持各种运算符，包括：

算术运算符：+, -, *, /, %
关系运算符：==, ===, !=, !==, <, >, <=, >=
逻辑运算符：&&, ||, !

let result = 10 + 5; // 15
let result = 10 == 10; // true

函数

函数是 JavaScript 中的核心概念之一：

function greet(name) {
  return "Hello, " + name;
}

let message = greet("Alice");
console.log(message); // Hello, Alice

图片

更多关于 JavaScript 的内容，您可以访问JavaScript 教程。



JavaScript is a widely-used programming language primarily used for web development. Here are some basic points about JavaScript syntax.

### Variable Declaration

There are several ways to declare variables in JavaScript:

- Using the `var` keyword
- Using the `let` keyword
- Using the `const` keyword

```javascript
var a = 10;
let b = 20;
const c = 30;

Data Types

JavaScript has the following basic data types:

number: Numbers
string: Strings
boolean: Boolean values
null: Null
undefined: Undefined
object: Objects

let x = 5; // number
let y = "Hello"; // string
let z = true; // boolean

Operators

JavaScript supports various operators, including:

Arithmetic operators: +, -, *, /, %
Relational operators: ==, ===, !=, !==, <, >, <=, >=
Logical operators: &&, ||, !

let result = 10 + 5; // 15
let result = 10 == 10; // true

Functions

Functions are a core concept in JavaScript:

function greet(name) {
  return "Hello, " + name;
}

let message = greet("Alice");
console.log(message); // Hello, Alice

Image

For more information about JavaScript, you can visit the JavaScript Tutorial.