<ol>
        <li>Sys.Application.init(event handle need Sys.Application.add_init(MyInit);</li>
        <li>Sys.Application.load (event handler function pageLoad(sender, args){} </li>
        <li>Sys.Application.unload (event handler function pageUnLoad(sender, args){}</li>
        <li>Sys.Application.disposing( inherit from Component class)</li>
        <li>Sys.Application.propertyChanged( inherit from Component class)</li>
        </ol>

        <ol>
        <li>Sys.WebForms.PageRequestManager.initializeRequest</li>
        <li>Sys.WebForms.PageRequestManager.beginRequest</li>
        <li>Sys.WebForms.PageRequestManager.pageLoading</li>
        <li>Sys.WebForms.PageRequestManager.pageLoaded</li>
        <li>Sys.WebForms.PageRequestManager.endRequest</li>
        </ol>

        <p>
        For detail see <a href="http://www.asp.net/AJAX/Documentation/Live/overview/AJAXClientEvents.aspx">this
        </a>
        </p>


        <pre data-sub="prettyprint:_">
        Sys.Application.add_init(applicationInit);
        //Sys.Application.add_load(applicationLoad);
        Sys.Application.add_unload(applicationUnload);

        function applicationInit(sender, args)
        {
        alert("application init");
        }

        function pageLoad(sender, args) {
        //function applicationLoad(sender, args) {
        alert("application load");
        }

        function applicationUnload(sender, args)
        {
        alert("application unload");
        }

        Sys.WebForms.PageRequestManager.getInstance().add_initializeRequest(pageRequestInitRequestHandler);
        Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(pageRequestManagerBeginRequestHandler);
        Sys.WebForms.PageRequestManager.getInstance().add_pageLoading(pageReqeustPageLoading);
        Sys.WebForms.PageRequestManager.getInstance().add_endRequest(pageRequestManagerEndRequestHandler);
        Sys.WebForms.PageRequestManager.getInstance().add_pageLoaded(pageRequestManagerLoadHandler);

        function pageRequestInitRequestHandler(sender, args)
        {
        alert("PageRequestManager initRequest");
        }

        function pageReqeustPageLoading(sender, args)
        {
        alert("PageRequestManager pageLoading");
        }

        function pageRequestManagerBeginRequestHandler(sender, args)
        {
        alert("PageRequestManager beginRequestr");
        }

        function pageRequestManagerLoadHandler(sender, args)
        {
        alert("PageRequestManager pageLoaded");
        }

        function pageRequestManagerEndRequestHandler(sender, args)
        {
        alert("PageRequestManager endRequest");
        }
        </pre>

        <p>
        For the initial load, the event sequence is PageRequestManager pageLoaded, application init, application load. For asynchronous call, is PageRequestManager initRequest, PageRequestManager beginRequest, PageRequestManager pageLoading, PageRequestManager pageLoaded, application load, PageRequestManager endRequest.
        </p>