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.
ThetoLowerCase() method ofString 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
js
toLowerCase()Parameters
None.
Return value
A new string representing the calling string converted to lower case.
Description
ThetoLowerCase() method returns the value of the string converted tolower case.toLowerCase() does not affect the value of the stringstr itself.
Examples
UsingtoLowerCase()
js
console.log("ALPHABET".toLowerCase()); // 'alphabet'Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-string.prototype.tolowercase |