Really cool js library that creates a user friendly, semantic html 5 compatible wysiwyg text editor that works in your browser.

a simple jQuery plugin that allows you to add a dynamically-resized background image to any page

HTML5media enables you to use HTML audio and video tags in all major browsers with a single line of code.

There are plenty of web-based chat clients out there. Most of them are built to emulate your instant messenger. They offer you tons of settings. They can join multiple networks, let you edit your profile, and even manage your message history.
Candy is different. It's built for your community.

Nice site that allows people to collaborate and share code snippets for useful tasks in all manor of languages.

Collection of php functions translated into javascript - makes JS a lot easier if you work primarily in PHP

Nice lightbox clone for Jquery

Really handy way to visualise the various ways of selecting content with JQuery,

Tiny (1KB) javascript tool that allows you to easily target specific browsers with CSS by adding a class to the html tag!

Handy JQuery / PHP Combo that allows uploading of an image and manual square thumbnail creation

Scary line of javascript which, when pasted into your address bar, makes the current page editable with WYSIWYG precision! Works in Safari, Firefox and IE7

Handy JQuery plugin for allowing users to select an area of an image. Ideal for online cropping etc.

Handy blog post on how to take an accessible data table and make it look like a chart using nothing more than the free Google Charts API and some JavaScript

Using a bit of javascript magic and some CSS it's possible to make upload forms that are far more usable than the default types!