The toLocaleUpperCase() method is used to convert a string to uppercase letters by using the current locale. The locale is based on the language settings of the browser. However, it does not have any effect on the original string. In most of the cases, toLocaleUpperCase() returns the same result as toUpperCase().
Its syntax is:- string.toLocaleUpperCase()
Its return is:- new string converted to uppercase according to current locale browser settings