乗算 (*)
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.
乗算演算子 (*) はオペランドの積を生成します。
試してみましょう
console.log(3 * 4);
// Expected output: 12
console.log(-3 * 4);
// Expected output: -12
console.log("3" * 2);
// Expected output: 6
console.log("foo" * 2);
// Expected output: NaN
構文
js
x * y;
例
数値を用いた乗算
js
2 * 2; // 4
-2 * 2; // -4
無限大との乗算
js
Infinity * 0; // NaN
Infinity * Infinity; // Infinity
非数との乗算
js
"foo" * 2; // NaN
仕様書
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-multiplicative-operators |