JavaScript判断前缀、后缀是否是空格的方法

// Js 判断后缀 String.prototype.endsWith = function(suffix) {  return this.indexOf(suffix,this.length - suffix.length)!==-1; };  // Js 判断前缀if (typeof String.prototype.startsWith != 'function') { // see below for better implementation! String.prototype.startsWith = function (str){ return this.indexOf(str) == 0; };}   // Js 判空(含全部是空格)String.prototype.IsNullEmptyOrSpace = function() {    if (this== null) return true;   return this.replace(/s/g, '').length == 0; };