// JavaScript Document
function isEmpty(str) {
            // Check whether string is empty.
            for (var intLoop = 0; intLoop < str.length; intLoop++)
               if (" " != str.charAt(intLoop))
                  return false;
            return true;
         }

         function checkRequired(f) {
            var strError = "";
            for (var intLoop = 0; intLoop < f.elements.length; intLoop++)
               if (null!=f.elements[intLoop].getAttribute("required")) 
                  if (isEmpty(f.elements[intLoop].value))
                     strError += "  " + f.elements[intLoop].name + "\n";
            if ("" != strError) {
               alert("Please enter your \n" + strError);
               return false;
            } else
            return true       
         }