// JavaScript Document
function insertRightContent(){
  var url = "AJAX_BE/item_RightContent.php?RelSubCatID=" + document.getElementById('RelSubCatID').value;
  document.getElementById('rightSection').innerHTML = "<img src='../AJAX_BE/images/loading.gif'/>";
  http.open("GET", url, true);
  http.onreadystatechange = handleHttpResponseRightContent;
 
  http.send(null);
}
function handleHttpResponseRightContent(){
  if(http.readyState == 4){
    document.getElementById('rightSection').innerHTML = http.responseText;
  }
}