I am looking for a lightweight JavaScript library, for use in secure environments where all users have recent browsers (IE 9, Firefox 4 for example).
I am looking for wrapper features like AJAX, animations and cross-domain messaging. I don’t care about the overhead to support older browsers (stuff like JSON parsing or querySelectorAll is native).
Any library to recommend?
Take a look at http://microjs.com/ – choose what type of library you’d like and it will show you all that come in under 5k.
Also take a look at Ender – http://ender.no.de – for composing your own library from other micro-frameworks.