function get_ajax_content(page,action,div) {
  var obj = false;

  if(navigator.appName == "Microsoft Internet Explorer") {
    obj = new ActiveXObject("Microsoft.XMLHTTP");
  } else {
    obj = new XMLHttpRequest();
  }
  obj.abort();
  obj.open("GET", "classes/ajax_server.php?page=" + page + "&action=" + action, true);
  obj.onreadystatechange=function() {
    if(obj.readyState == 4) {
      document.getElementById(div).innerHTML = obj.responseText;
    }
  }
  obj.send(null);
}