小于等于（<=）

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

小于等于运算符（<=）在左操作数小于等于右操作数时返回 true，否则返回 false。

尝试一下

语法

js
x <= y

描述

操作数比较使用与小于运算符相同的算法，除了相等的值（在尝试转换后）会返回 true。

示例

字符串与字符串比较

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

字符串与数值比较

js
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

数值与数值比较

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

数值与大整型比较

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

比较 Boolean、null、undefined 和 NaN

js
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

规范

Specification
ECMAScript Language Specification
# sec-relational-operators

浏览器兼容性

BCD tables only load in the browser

参见