- They're one and the same - for an history on JavaScript watch the Douglas Crockford webcasts on YouTube.
http://youtu.be/_DKkVvOt6dk
http://youtu.be/hQVTIJBZook
2,3,4. Start with this http://eloquentjavascript.net/
Libraries like jQuery do a good job in normalising behaviour across browsers.
I think this is what you are looking for http://dochub.io/#javascript/