String.prototype.trim = function() {
a = this.replace(/^\s+/, '');
return a.replace(/\s+$/, '');
};

String.prototype.str_replace = function(search, replace) {
  var subject = this;
  var result = "";
  var  oldi = 0;
  for (i = subject.indexOf (search)
     ; i > -1
     ; i = subject.indexOf (search, i))
  {
    result += subject.substring (oldi, i);
    result += replace;
    i += search.length;
    oldi = i;
  }
  return result + subject.substring (oldi, subject.length);
}
function isValidEmail(s)
{
	var a = false;
	var res = false;
 	if(typeof(RegExp) == 'function')
 	{
		 var b = new RegExp('abc');
		 if(b.test('abc') == true){a = true;}
 	}
 	if(a == true)
 	{
 	 	reg = new RegExp('^([a-zA-Z0-9\\-\\.\\_]+)'+'(\\@)([a-zA-Z0-9\\-\\.]+)'+'(\\.)([a-zA-Z]{2,4})$');
 	 	res = (reg.test(s));
 	}
 	else
 	{
 	 	res = (s.search('@') >= 1 && s.lastIndexOf('.') > s.search('@') && s.lastIndexOf('.') >= s.length-5)
 	}
 	return(res);
}