The Ajax experience brought together the foremost experts on the subject, take a look at the content and presentations given by some of these Ajax guru's in this post by Marc Grabanski.
Ben Galbraith - Co-founder of Ben gave an overview of Ajax and started getting his hands right into some demo code. He showed a very basic implementation of the XMLHttpRequest object to send data to the server. The biggest lesson from Ajax that we learned is, "JavaScript doesn't suck after all". Tools to develop ajax are Aptana and Firebug - check and check. I absolutely love these tools and use them every day. Ajax is somewhat slow and processor intensive, but Tamarin is a project that will speed up processing of JavaScript. Adobe's ActionScript interpreter is faster (up to 10 times) and they donated it to Mozilla. Now Mozilla is working on implementing Adobe's ActionScript engine to interpret JavaScript faster in the browser.
John Resig - Mozilla Three basic ways to implement JavaScript with libraries. * Level 1 - Easily drag and drop in widgets into your web application. * Level 2 - Some assembly required. Set of functions that allow you to not worry about the browser bugs. JavaScript Frameworks - Aids writing JavaScript code. * Level 3 - Directly interact with the DOM API. Dealing directly with DOM and dealing directly with browser quirks and bugs. You should use a JavaScript library so you don't have to deal with problems people have already solved. Hence wasting a lot of time.
Read Marc's entire post: