JavaScript String toLocaleLowerCase() method
converts a string to lower case letters, using current locale

toLocaleLowerCase() method converts a string to lower case letters, using current locale.

syntax

toLocaleLowerCase(locales)

locales (optional). A string with a BCP 47 language tag, or an array of such strings.

Indicates the locale to be used to convert to lower case according to any locale-specific case mappings.

The locale is based on the language settings of the browser.

toLocaleLowerCase() method does not change the original string.

toLocaleLowerCase() returns the same result as toLowerCase(),
except for locales that conflict with the regular Unicode case mappings (such as Turkish).

\u0130 represents a capital letter I with a dot above: İ

as in İstanbul.

'\u0130'.toLocaleLowerCase('tr-TR') === 'i'; returns true.

'\u0130'.toLocaleLowerCase('en-GB') === 'i'; returns false.

If incorrect locale information is provided RangeError will be thrown.

syntax 1 description
convert myString to lower case letters using current locale
myString.toLocaleLowerCase()
syntax 2 description
convert myString to lower case letters using selected locale
myString.toLocaleLowerCase(locales)