Believe it or not but jQuery has been around for 4 years now. Over the years the library has really become a full-fledged and feature rich API. Late last week, the 1.4 release of jQuery hit the streets and the major focus of the 1.4 release is performance. John Resig, the creator of jQuery did some extensive tuning and found ways to reduce the complexity of the internal function calls which led to some phenomenal results:
Obviously, the performance gains found in the 1.4 library make it a worthwhile upgrade. Also as a developer, don't sweat the upgrade. The process should go very smoothly because the jQuery team maintained the signatures of all public functions. Therefore, you will probably not need to change your code. There is a documented list of potentially-breaking changes to be aware of but overall things should go very smoothly.
The entire jQuery API site has also been redesigned as well to go along with the 1.4 release. The main landing page has been optimized so you can get help on the methods you want immediately. The main page has every single jQuery method, property, and selector listed on it – you can scroll through the full list, or browse through the extensive category list on the side, or you can simply begin typing. When you type on the jQuery API homepage all the API entries will be instantly filtered.
As always, there are two versions of the jQuery library you can download. The minified version (23kb GZipped) which is for production purposes and the uncompressed version (154 kb) which is handy for debugging and reading. If you are a jQuery veteran then you may have noticed that the minified version has actually shrunk by 13% from the 1.3 to 1.4 release. These is also a pleasant side effect of the work done by John Resig to reduce the complexity of the overall code base.
Finally, if you want to out-host your jQuery library you can simply add a reference to the copy on the lightning fast Google edge cache servers at: http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js.
Happy Birthday jQuery!