ExtJS
Google AJAX Libraries API
Do you use a JavaScript library — such as jQuery, Prototype, or MooTools — on one (or more) of your websites? That probably adds a good 18-120 kilobytes to your pages’ total size, adding more time to users’ download time.
Simple login form with ExtJS and PHP – beginners tutorial
Step by step tutorial about creating simple auth form by ExtJS (AJAX framework) and PHP (at server side). Detailed overview how to work with form widgets in ExtJS.