Here you can find the source of trim()
// Trim//from ww w.j a v a 2 s.co m String.prototype.trim = function () { return this.replace(/^\s+|\s+$/g, ""); }
String.prototype.trim = (function() { var trimRegex = /(^\s+|\s+$)/g; return function() { return this.replace(trimRegex, ''); }; }());
String.prototype.trim = (function() { var trimRegex = /(^\s+|\s+$)/g; return function() { return this.replace(trimRegex, ''); };
String.prototype.trim = function(){ return this.replace(/(^[\\s]*)|([\\s]*$)/g, "");
String.prototype.trim = function trim() { return this.replace(/^\s+|\s+$/g, ''); };
String.prototype.trim = function(){ return this.replace(/^(\s|\u00A0)+/,'').replace(/(\s|\u00A0)+$/,'');
String.prototype.trim = function () { return this.replace(/^\s+|\s+$/, ""); };
'use strict'; String.prototype.trim = function(){ return /^\s*([\d\D]*?)\s*$/.exec(this)[1]; };
String.prototype.trim=function(){ return this.replace(/^\s+|\s+$/g,"");
String.prototype.trim = function () { return this.replace(/^\s+/, ""); };