# Less than or equal (<=)

## 在此页

The less than or equal operator ( ``` <= ``` ) returns ``` true ``` if the left operand is less than or equal to the right operand, and ``` false ``` 否则。

## 句法

``` x <= y
```

## 描述

The operands are compared using the Abstract Relational Comparison algorithm. See the documentation for the Less than operator for a summary of this algorithm.

## 范例

### String to string comparison

```console.log("a" <= "b");     // true
console.log("a" <= "a");     // true
console.log("a" <= "3");     // false
```

### String to number comparison

```console.log("5" <= 3);       // false
console.log("3" <= 3);       // true
console.log("3" <= 5);       // true
console.log("hello" <= 5);   // false
console.log(5 <= "hello");   // false
```

### Number to Number comparison

```console.log(5 <= 3);         // false
console.log(3 <= 3);         // true
console.log(3 <= 5);         // true
```

### Number to BigInt comparison

```console.log(5n <= 3);        // false
console.log(3 <= 3n);        // true
console.log(3 <= 5n);        // true
```

### Comparing Boolean, null, undefined, NaN

```console.log(true <= false);  // false
console.log(true <= true);   // true
console.log(false <= true);  // true
console.log(true <= 0);      // false
console.log(true <= 1);      // true
console.log(null <= 0);      // true
console.log(1 <= null);      // false
console.log(undefined <= 3); // false
console.log(3 <= undefined); // false
console.log(3 <= NaN);       // false
console.log(NaN <= 3);       // false
```

## 浏览器兼容性

 Desktop Mobile Server Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100

## 另请参阅

1. JavaScript
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3. 完整初学者
4. JavaScript 指南
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