function check_Email(email) 
{
    var reg = /^[a-zA-Z0-9_\.-]+@([a-zA-Z0-9-]+\.)+[a-zA-Z0-9]{2,4}$/;
		  if(reg.test(email)) {
			 return true; }
		  else {
			 alert(email + " is not a valid e-mail address. Please enter a valid e-mail address."); }
			 
		  email.focus();		
		 return false;
}