function checkEmail(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);
}