var firstrun = 0;
function pageLoad() {
    if (firstrun == 0){
    var manager = Sys.WebForms.PageRequestManager.getInstance();
    manager.add_beginRequest(OnBeginRequest);
    manager.add_endRequest(OnEndRequest);
    firstrun = 1;
    }
    try {myPageInit()} catch(e) {}
}
var lcPostbackElement;
var OriginalTextValue;
function OnBeginRequest(sender, args) {
    lcPostbackElement = args.get_postBackElement();
    if (lcPostbackElement.id.toLowerCase().indexOf("btn") != -1) {
        //lcPostbackElement.disabled = true;
        try {
            OriginalTextValue = document.getElementById(lcPostbackElement.id).value;
            document.getElementById(lcPostbackElement.id).value = 'Een momentje...'; 
        }
        catch (e) { }
    }
}
function OnEndRequest(sender, args) {
    if (lcPostbackElement.id.toLowerCase().indexOf("btn") != -1) {
        //lcPostbackElement.disabled = false;
        try {
            document.getElementById(lcPostbackElement.id).value = OriginalTextValue;
        }
        catch (e) { }
    }
}