window.onerror = function(msg, url, lineNo, columnNo, error) {
    alert([
        msg,
        'file: ' + url,
        'lineNo: ' + lineNo,
        'columnNo: ' + columnNo,
        'error: ' + error
    ].join('\n'));
};

var event = new UIEvent('scroll');

var event = document.createEvent(‘UIEvent’);
event.initUIEvent(‘scroll’, false, true);

var event;
try {
    event = new UIEvent('scroll');
} catch (e) {
    event = document.createEvent('UIEvents');
    event.initUIEvent('scroll', false, true);
}

element.dispatchEvent(event);