Make browser tab flash a notification

It's not possible to change the background of a browser tab, at least not consistently across all.

As Josiah has mentioned, setInterval can be used to create a flashing page title.

This javascript makes use of it:

var PageTitleNotification = {
    Vars:{
        OriginalTitle: document.title,
        Interval: null
    },    
    On: function(notification, intervalSpeed){
        var _this = this;
        _this.Vars.Interval = setInterval(function(){
             document.title = (_this.Vars.OriginalTitle == document.title)
                                 ? notification
                                 : _this.Vars.OriginalTitle;
        }, (intervalSpeed) ? intervalSpeed : 1000);
    },
    Off: function(){
        clearInterval(this.Vars.Interval);
        document.title = this.Vars.OriginalTitle;   
    }
}

This can be used like:

PageTitleNotification.On("User logged out!");

See my following blog post for more info:

http://curtistimson.co.uk/js/create-a-flashing-tab-notification-page-title/

You can change the title of the page (this should also change the text in the tab).

document.title = 'New title';

Additionally you could do this in a setInterval back and forth between the page title, and the information you are attempting to show the user. I have seen this behavior on gmail with incoming chat communication.