Chrome & Firefox Desktop Notifications

HTML

<button onclick="notifyMe()">Notify me!</button>

JavaScript

function notifyMe() {
    // Let's check if the browser supports notifications
    if (!("Notification" in window)) {
        alert("This browser does not support desktop notification");
    }

    // Let's check if the user is okay to get some notification
    else if (Notification.permission === "granted") {
        // If it's okay let's create a notification
        var notification = new Notification("Hi there!");alert(3);
    }

    // Otherwise, we need to ask the user for permission
    // Note, Chrome does not implement the permission static property
    // So we have to check for NOT 'denied' instead of 'default'
    else if (Notification.permission !== 'denied') {
        Notification.requestPermission(function (permission) {
alert(4);
            // Whatever the user answers, we make sure Chrome stores the information
            if (!('permission' in Notification)) {
                Notification.permission = permission;
            }

            // If the user is okay, let's create a notification
            if (permission === "granted") {
                var notification = new Notification("Hi there!");
            }
        });
    }

    // At last, if the user already denied any notification, and you 
    // want to be respectful there is no need to bother him any more.
}