相減運算子（-）
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.
相減運算子（-）是用來將兩個值進行相減，並得出它們的差值。
嘗試一下
console.log(5 - 3); // Expected output: 2 console.log(3.5 - 5); // Expected output: -1.5 console.log(5 - "hello"); // Expected output: NaN console.log(5 - true); // Expected output: 4 語法
js
x - y 範例
數字相減
js
5 - 3; // 2 3 - 5; // -2 非數字之間的相減
js
"foo" - 3; // NaN 規範
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-subtraction-operator-minus |