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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 2015年7月.
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: -1console.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; // 3bar -= "foo"; // NaN规范
| Specification |
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| ECMAScript® 2026 Language Specification # sec-assignment-operators |