JavaScript Lowercase
toLowerCase() returns a new string with every character converted to lower case. It returns a copy — strings are immutable in JavaScript, so the original never changes.
Syntax
str.toLowerCase()Examples
| Input | Arguments | Output |
|---|---|---|
| "HELLO World" | — | "hello world" |
| "ÀÉÎ" | — | "àéî" |
| ↳ Handles accented characters too. | ||
When to use it
- Normalise user input before comparing (emails, usernames).
- Build case-insensitive search filters.
Gotchas
- Locale-specific casing (e.g. Turkish "İ") may need toLocaleLowerCase() instead.
Try it live
Type your input and see Lowercase transform it instantly.
Want to go further? Chain Lowercase with other functions in the visual Playground — pipe one output into the next and watch your data transform.