gistfile1.js

function notify(title, body, icon, callback) {
    if (window.Notification) {
        function donotify() {
            var notification = new Notification(title, {
                body: body,
                icon: icon
            });
            notification.onclick = callback;
        }
        if (Notification.permission === 'granted') {
            donotify();
        } else if (Notification.permission !== 'denied') {
            Notification.requestPermission(function(permission) {
                if (permission !== 'granted') return;
                donotify();
            });
        }
    } else {
        var havePermission = window.webkitNotifications.checkPermission();
        if (havePermission === 0) {
            var notification = window.webkitNotifications.createNotification(
                icon || null,
                title,
                body
            );
            notification.onclick = callback;
            notification.show();
        } else {
            window.webkitNotifications.requestPermission();
        }
    }
}