Javascript Widgets

I am wanting to make a Javascript widget th开发者_如何学Goat can pull "X" number of the most recent posts from a RSS Feed.

My question is:

What is the fundamentals that i should be looking into in order to achieve this?

• AJAX or JSON/script-tag methods of retrieving remote data from the browser (or writing a server-side proxy to retrieve data and set it up for your widget to consume from the browser)
• DOM manipulation, for formatting your data into markup on a page
• CSS for styling your markup

Yahoo! Pipes can be very helpful for this sort of thing... this Pipe can take your X and your RSS feed URL and return JSON for you to work with in JavaScript, saving tons of time... http://pipes.yahoo.com/pipes/pipe.info?_id=2FV68p9G3BGVbc7IdLq02Q