String.prototype.toLowerCase()
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.
toLowerCase() 函式会回传将字符串转换为英文小写字母后的结果。
嘗試一下
const sentence = "The quick brown fox jumps over the lazy dog.";
console.log(sentence.toLowerCase());
// Expected output: "the quick brown fox jumps over the lazy dog."
语法
js
str.toLowerCase()
回传值
回传一组将原字串英文内容转换成英文小写字母后的结果。
描述
The toLowerCase() 函式会回传一组将原字符串英文内容转换成英文小写字母后的结果。 toLowerCase() 并不会影响到原字符串 str 的内容值。
范例
使用 toLowerCase()
js
console.log("ALPHABET".toLowerCase()); // 'alphabet'
规范
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-string.prototype.tolowercase |