how to convert first letter of string to uppercase and all the others lowercase in javascript code example

Example 1: javascript capitalize words

//capitalize only the first letter of the string. 
function capitalizeFirstLetter(string) {
    return string.charAt(0).toUpperCase() + string.slice(1);
}
//capitalize all words of a string. 
function capitalizeWords(string) {
    return string.replace(/(?:^|\s)\S/g, function(a) { return a.toUpperCase(); });
};

Example 2: capitalize first carater js

String.prototype.capitalize = function() {
  return this.charAt(0).toUpperCase() + this.slice(1)
}