[Javascript] - Ajax로 페이지 Call하는법

<script>
function Callajax(url){

 try{
  if(window.XMLHttpRequest){
   tXhttp = new XMLHttpRequest();
  } else if(window.ActiveXObject) {
   try {
    tXhttp = new ActiveXObject("Msxml2.XMLHTTP");
   } catch (e1) {
    try {
     tXhttp = new ActiveXObject("Microsoft.XMLHTTP");
    } catch (e2) {
     
    }
   }
  }
 }catch(e3){
  try {
   tXhttp = new ActiveXObject("Msxml2.XMLHTTP");
  } catch (e1) {
   try {
    tXhttp = new ActiveXObject("Microsoft.XMLHTTP");
   } catch (e2) {
         
   }
  }
 }

 if (tXhttp != null){
  tXhttp.open("GET", url, false);
  tXhttp.send();   
   if (tXhttp.readyState == 4) {
    menuText = tXhttp.responseText;    
   }
 }

 return menuText;
}

function moviestart(lnk){
 if (lnk == ""){
  var url = "./movie_form.php";
 }else{
  var url = lnk;
 }
 var rtn = Callajax(url);
 document.getElementById("movielist").innerHTML = rtn;
}

window.onload = function(){
 moviestart("");
}
</script>