$(function () {

    try {
        // Get the instance of PageRequestManager.
        var prm = Sys.WebForms.PageRequestManager.getInstance();
        // Add initializeRequest and endRequest
        prm.add_initializeRequest(prm_InitializeRequest);
        prm.add_endRequest(prm_EndRequest);
    } catch (e) {

    }
    

});

// Called when async postback begins
function prm_InitializeRequest(sender, args) {
    try {
        // get the divImage and set it to visible
        var panelProg = $get('divProgressImage');
        panelProg.style.display = '';

        // Disable button that caused a postback
        $get(args._postBackElement.id).disabled = true;
    } catch (e) {
        panelProg.style.display = 'none';
        $get(sender._postBackSettings.sourceElement.id).disabled = false;
    }
   
}

// Called when async postback ends
function prm_EndRequest(sender, args) {

    try {
        // get the divImage and hide it again
        var panelProg = $get('divProgressImage');
        panelProg.style.display = 'none';

        // Enable button that caused a postback
        $get(sender._postBackSettings.sourceElement.id).disabled = false;
    } catch (e) {

    }
    
}// JavaScript source code