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.
A useful overview / introduction of the jQuery library, covering using selectors and XPath expressions to target specific elements in a document, simple Ajax requests, the basic animations available, restructuring a document, creating jQuery plugins.