function isNumeric(input_string) {
	
   var numbers = "0123456789";
   var single_char;
   var result_flag = true;

   if (input_string.length == 0) return false;

   //  See if input_string contains any non-numeric characters
   for (i = 0; i < input_string.length && result_flag == true; i++) {
      single_char = input_string.charAt(i);
      if (numbers.indexOf(single_char) == -1) {
         result_flag = false;
      }
   }
	 
   return result_flag;
	 
}