/*
function Inint_AJAX() {
   try { return new ActiveXObject("Msxml2.XMLHTTP"); } catch(e) {} //IE
   try { return new ActiveXObject("Microsoft.XMLHTTP"); } catch(e) {} //IE
   try { return new XMLHttpRequest(); } catch(e) {} //Native Javascript
   alert("XMLHttpRequest not supported");
   return null;
};

//dochange ????????????????????????? ?????? Combobox ?????????????????? AJAX ????????????????????????? Server
function dochange(src, val) {
  var req = Inint_AJAX();
  req.onreadystatechange = function () { 
    if (req.readyState==4) {
      if (req.status==200) {
        document.getElementById(src).innerHTML=req.responseText; //????????????
      } 
    }
  };
  req.open("GET", "includes/province.php?data="+src+"&val="+val); //????? connection
  req.setRequestHeader("Content-Type", "application/x-www-form-urlencoded"); // set Header
  req.send(null); //??????
}

//????????????????????? id ??? Combobox ????????????????
function banchange() {
  document.getElementById('result').innerHTML=sel.cat1.value+', '+sel.cat2.value+', '+sel.cat3.value+', '+sel.Pid.value;
}

//???????????????????????? ????? ??????
window.onLoad=dochange('cat1', -1); 
*/
<!--
function MM_jumpMenu(targ,selObj,restore){ //v3.0
  eval(targ+".location='"+selObj.options[selObj.selectedIndex].value+"'");
  if (restore) selObj.selectedIndex=0;
}
//-->