JS Statistics page online time script _ajax related

Per xxxxx millisecond detection is online once,
Tr_count after the user set to change the state of suspended animation (that is, not the current page activity, AFK ...)
When the page is closed, the time to send the stay

/**//* ----------------------------------------------------------------------------
* Script Name:online.js
* Last modified:2008-4-13 22:25
* Author:meyu
* Copyright (c) 2008
* Purpose: Tracking online time
* ----------------------------------------------------------------------------*/

function tr_xmlhttpobject (URL) ... {
This. Xmlhttp=null;
This.url=url;
This.init=function () ... {
if (window. XMLHttpRequest) ... {
This. Xmlhttp=new XMLHttpRequest ();
}else if (window. ActiveXObject) ... {
This. Xmlhttp=new ActiveXObject ("Microsoft.XMLHTTP");
}
};
This.init ();
This.senddata=function (param) ... {
With (this. XMLHttp) ... {
Open (' Get ', this.url+ (param| | '), TRUE);
Send (NULL);
}
};
}
if (/flag=flush/i.test (Window.location.search)) ... {
var tr_count=0;
var tr_x=new tr_xmlhttpobject (Window.location.href.replace (/&?: flush_count=) (d+)/I,
function (a,d) ... {
Tr_count=parseint (d);
Return "";
})
);
function Send () ... {
tr_count++;
if (Tr_count < 120) ... {
Tr_x.senddata (' &flush_count= ' +tr_count);
}
}
Window.setinterval (send,30000);
Window.onunload=function () ... {tr_x.senddata (' &flush_count= ' +tr_count);};
}