//main menu
    var img36="/Portals/_default/Skins/NVPortal/Images/Menus/trangchu.jpg";
    var img36_over="/Portals/_default/Skins/NVPortal/Images/Menus/trangchu_over.jpg";
    var img230="/Portals/_default/Skins/NVPortal/Images/Menus/gioithieu.jpg";
    var img230_over="/Portals/_default/Skins/NVPortal/Images/Menus/gioithieu_over.jpg";
    var img231="/Portals/_default/Skins/NVPortal/Images/Menus/chaobao.jpg";
    var img231_over = "/Portals/_default/Skins/NVPortal/Images/Menus/chaobao_over.jpg";
    var img227="/Portals/_default/Skins/NVPortal/Images/Menus/timmua.jpg";
    var img227_over = "/Portals/_default/Skins/NVPortal/Images/Menus/timmua_over.jpg";
    var img188="/Portals/_default/Skins/NVPortal/Images/Menus/tuvan.jpg";
    var img188_over="/Portals/_default/Skins/NVPortal/Images/Menus/tuvan_over.jpg";
    var img166="/Portals/_default/Skins/NVPortal/Images/Menus/tintuc.jpg";
    var img166_over="/Portals/_default/Skins/NVPortal/Images/Menus/tintuc_over.jpg";
    var img54 = "/Portals/_default/Skins/NVPortal/Images/Menus/vbpq.jpg";
    var img54_over = "/Portals/_default/Skins/NVPortal/Images/Menus/vbpq_over.jpg";
    var img55 = "/Portals/_default/Skins/NVPortal/Images/Menus/lienhe.jpg";
    var img55_over = "/Portals/_default/Skins/NVPortal/Images/Menus/lienhe_over.jpg";
    function changeimage(imgid,isover) {
        var img = document.getElementById(imgid);
        if (img != null)
        {
            if (isover==0 & imgid != imgSelected){
                //img.src=eval(imgid ); 
            }
            else {
             document.getElementById('img36').src=img36;
             document.getElementById('img230').src=img230;
             document.getElementById('img231').src=img231;
             document.getElementById('img227').src=img227;
             document.getElementById('img188').src=img188;
             document.getElementById('img166').src = img166;
             document.getElementById('img54').src = img54;
             document.getElementById('img55').src = img55;
             img.src=eval(imgid+ '_over');
             //alert(test);
            }
        }   
        else
        {
            //alert('test1');
        }
    }
    
    function getParam(param) {
      var query = window.location.search.substring(1);
      var parms = query.split('&');
      for (var i=0; i<parms.length; i++) {
        var pos = parms[i].indexOf('=');
        if (pos > 0) {
           var key = parms[i].substring(0,pos).toLowerCase();
           var val = parms[i].substring(pos+1);
           if(key == param.toLowerCase()) 
               return val;
        }
      }
      return null;
  }
  function reWriteMenu() {
      delayhide = setTimeout("changeimage()", 1000);
  }
  function clear_delayhide() {
      if (window.delayhide)
          clearTimeout(delayhide)
  }