Problém s prenášaním hodnoty medzi function pri ajaxe

function createObject() {
 var req_type;
 var brow = navigator.appName;
 if(brow == 'Microsoft Internet Explorer'){
  req_type = new ActiveXObject('Microsoft.XMLHTTP');
 }
 else{ 
  req_type = new XMLHttpRequest();
 }
 return req_type;
}

var htt = createObject();
function ac(dbto,dckn) {
 var dno = 'c' + dbto ;
htt.open('get', 'lalala.php');
htt.onreadystatechange = asR;
htt.send(null);
}

function asR(dnoo) {
  if(htt. == 4){
   e = document.getElementById(dnoo);
   var res = htt.responseText;
    if(res!=''){
     e.innerHTML=res;
     e.style.display='block';
    }
    else {
     e.style.display='none';
    }
  }
}

htt.onreadystatechange = asR;

htt.onreadystatechange = asR(dno);