udacity_ext.js

// ==UserScript==
// @name            Udacity EXT - Auto next video&quiz
// @description     Udacity Extension -- Automatically go to the next video or quiz question upon reaching the end of the current one
// @namespace       http://sepczuk.com/
// @version         0.2
// @include         http://www.udacity.com/view*
// @match           http://www.udacity.com/view*
// @copyright       2012, Damian Sepczuk, Hugo Lopes Tavares
// ==/UserScript==

function mainWrapper(){
    function main(){
        if (window.App.player === undefined) {
            setTimeout(main, 300);
            return;
        }
        
        App.player.addEventListener('onStateChange', function(p){
            if (p.data === YT.PlayerState.ENDED) {
                $('#course-next-button .button').click();
            }
        })
    };

    main();
};


if (!document.xmlVersion) {
    var script = document.createElement('script');
    script.appendChild(document.createTextNode('('+ mainWrapper +')();'));
    document.documentElement.appendChild(script);
}

1- I notice that you create mainWrapper being self callable, why don't you do the same with the main function?:

function main(){
...
}();

2- if you jquery to make the click, why can't you use in the rest of the code ?

3- when you make the click you're selecting an element with a specific id and class, can't you select just by the id (theoretically the page must have just one element with that id)

my changes:
https://gist.github.com/2707337

I got ride of the mainWrapper function, but you did this function because of the timeout right?

This gist is based on this script: http://userscripts.org/scripts/review/126694, and I only adapted it.

I just "fixed" it to work with the new Udacity UI, made no refactoring/improvement :-)

ok then.. =P