减法赋值(-=)

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.

减法赋值-=)运算符从变量中减去右操作数的值,并将结果赋值给该变量。

尝试一下

let a = 2;

console.log((a -= 3));
// Expected output: -1

console.log((a -= "Hello"));
// Expected output: NaN

语法

js
x -= y // x = x - y

示例

使用减法赋值

js
let bar = 5;

bar -= 2; // 3
bar -= "foo"; // NaN

规范

Specification
ECMAScript® 2025 Language Specification
# sec-assignment-operators

浏览器兼容性

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
Subtraction assignment (x -= y)

Legend

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Full support
Full support

参见