String.prototype.toLowerCase() - JavaScript | MDN (original) (raw)

Baseline

Widely available

The toLowerCase() method of String values returns this string converted to lower case.

Try it

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."

Syntax

Parameters

None.

Return value

A new string representing the calling string converted to lower case.

Description

The toLowerCase() method returns the value of the string converted to lower case. toLowerCase() does not affect the value of the stringstr itself.

Examples

Using toLowerCase()

console.log("ALPHABET".toLowerCase()); // 'alphabet'

Specifications

Specification
ECMAScript® 2026 Language Specification # sec-string.prototype.tolowercase

Browser compatibility

See also