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; 
};