var req;
      if(window.XMLHttpRequest) { 
         req = new XMLHttpRequest();
         if (req.overrideMimeType) {
            req.overrideMimeType('text/xml');
         }
      }
      else if (window.ActiveXObject) { 
        try {
          req = new ActiveXObject("Msxml2.XMLHTTP");
        }catch (e) {
          try {
            req = new ActiveXObject("Microsoft.XMLHTTP");
          } catch (e) {}
        }
      }
      
   function prom(){
      
      req.open("POST","/online.do?method=updateInfo",false);
      req.setRequestHeader("CONTENT-TYPE","application/x-www-form-urlencoded"); 
      req.send(); 

   }
   
   setInterval("prom();",5*60*1000);   //5分钟更新一次在线时间   
   
   window.onbeforeunload = function(){
       if(event.clientX>document.body.clientWidth)
      {
        //关闭浏览器
        req.open("POST","/online.do?method=deleteInfo",false);
        req.setRequestHeader("CONTENT-TYPE","application/x-www-form-urlencoded"); 
        req.send(); 
      }
   }