function verifyItemNum(form,maximum){
  //list all the dropdown list
  //get the value
  //get the sum
  var tag = form.getElementsByTagName('select');
  var x =0;
  var sum = 0;
  for(x=0; x<tag.length; x++){

    var ele = tag[x]; //.getAttribute('id');

    var tmpValue =  ele.options[ele.selectedIndex].value;

    sum = sum + parseInt(tmpValue);

  }
  if(sum != maximum) {
   alert("You have chosen " + sum +" item(s). Please select exactly "+ maximum + " items in total to proceed" );
   return false;
   }
   else return true;
}

function MM_validateForm() { //v4.0
  if (document.getElementById){
    var i,p,q,nm,test,num,min,max,errors='',args=MM_validateForm.arguments;
    for (i=0; i<(args.length-2); i+=3) { test=args[i+2]; val=document.getElementById(args[i]);
      if (val) { nm=val.name; if ((val=val.value)!="") {
        if (test.indexOf('isEmail')!=-1) { p=val.indexOf('@');
          if (p<1 || p==(val.length-1)) errors+='- '+nm+' must contain an e-mail address.\n';
        } else if (test!='R') { num = parseFloat(val);
          if (isNaN(val)) errors+='- '+nm+' must contain a number.\n';
          if (test.indexOf('inRange') != -1) { p=test.indexOf(':');
            min=test.substring(8,p); max=test.substring(p+1);
            if (num<min || max<num) errors+='- '+nm+' must contain a number between '+min+' and '+max+'.\n';
      } } } else if (test.charAt(0) == 'R') errors += '- '+nm+' is required.\n'; }
    } if (errors) alert('The following error(s) occurred:\n'+errors);
    document.MM_returnValue = (errors == '');
} }