// for email and phone
function checkEmail(email ) {
              var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
              if (!filter.test(email)) {
                        return false;
            }
            return true;
}
function isNumber (s)
{
      var i;

      for (i = 0; i < s.length; i++)
      {
         var c = s.charAt(i);

         if (!isDigit(c)) return false;
      }

      return true;
}
function isEmpty(s)
   {
      return ((s == null) || (s.length == 0))
   }

   function isDigit (c)
   {
      return ((c >= "0") && (c <= "9"))
   }