请教objxmlhttp

function getpicinfo_fun(obname,obvale,page)
{
// str=escape(obname)+"="+escape(obvale);
 str=obname+"="+obvale;
 try  
   {  
         objxmlhttp = new ActiveXObject("MSXML2.XMLHttp");  
   }  
  catch(e)  
   {  
          try  
           {  
                objxmlhttp = new ActiveXObject("Microsoft.XMLHttp");  
           }  
          catch(e)
           {}
    } 
objxmlhttp.open("post",page,false);
objxmlhttp.setrequestheader("content-type","application/x-www-form-urlencoded");
objxmlhttp.setrequestheader("content-length",str.length);
objxmlhttp.send(str);
return objxmlhttp.responseText;}        function displaySubMenu(li) 
{          
   
getpicinfo_fun("cs",li.id,"index.asp");
     
}
鼠标移动到主页的菜单时，执行displaySubMenu，这个函数功能是想重新执行主页index.asp，并传递菜单的ID参数给主页，最终刷新主页上的内容。该怎么做。我试了下，没有反应