Sys.WebForms.PageRequestManager.getInstance().add_pageLoaded(PageLoadedHandler);
Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(disableControls);

var submitted = false;

function disableControls() {
    submitted = true;
    // Disable input controls on the SIF Form
    $("#SIFForm1C input").attr('disabled', true);

}

function enableControls() {
    submitted = false;
    // Re-enable input controls on the SIF Form
    $("#SIFForm1C input").attr('disabled', false);
}

function PageLoadedHandler(sender, args) {
    var updatedPanels = args.get_panelsUpdated();

    var iLen;
    for (var i = 0; i < updatedPanels.length; i++) {
        iLen = updatedPanels[i].id.length;
        if (iLen >= 14) {
            if (updatedPanels[i].id.substring(iLen, iLen - 14) == "updRequestInfo") {
                submitted = false;
                //enableControls();
                return;
            }
        }
    }
}

function submit_click() {
    if (submitted) {
        return false;
    }
    else {
        submitted = true;
        //disableControls();
        return true;
    }
}