function getXmlHttpRequest() {
    if(window.ActiveXObject){
          try{
                  return new ActiveXObject("Msxml2.XMLHTTP");
          } catch(e) {
                  try{
                    return new ActiveXObject("Microsoft.XMLHTTP");
                  }catch(e2){
                    return null;
                  }
          }
    } else if(window.XMLHttpRequest){
          return new XMLHttpRequest();
    }else{
          return null;
    } 
 }
 
 // ajax가 필요한 영역에 공통사용
 function include_ajax(div_id,url){
  var xmlhttp = getXmlHttpRequest();
  if(url){
    xmlhttp.open("GET", url, true); 
    xmlhttp.onreadystatechange = function() {
    if(xmlhttp.readyState == 4) {
    if(xmlhttp.status == 200) {
      document.getElementById( div_id ).innerHTML = xmlhttp.responseText;
    } else {
      }
    }
  }
  xmlhttp.send(null);
  }
  return false;
 }