Simon Willison blogs about how JQuery won him over. From its faddish start based around CSS selectors (getElementsBySelector), and method chaining, Simon now sees the library in a new light. Simon shows how jQuery supports modern development best practice such as namespaces, giving a quick nod to the richness of jQuery selectors (DOM, CSS and XPath). JQuery's event handling looks natural and offers an event when the dom is ready. It exposes custom events for non-trivial Ajax requests. Simon's so convinced about jQuery that he's willing to overlook his rule that developers should know how a library works before using it.
LowPro is a scripting extension to Prototype written by Dan Webb to make unobtrusive DOM Scripting much easier. Included are an onReady event, adding behaviour using CSS selectors, fixing the this reference to always refer to the element within events, and a mechanism for triggering events.
IE7 is a JavaScript library to make IE behave like a standards-compliant browser. It fixes many CSS issues and makes transparent PNG work correctly under IE5 and IE6.