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® 2026 Language Specification # sec-assignment-operators |