libNog is a 9k library to provide somewhat easier browser-independence. It is not yet complete, and will be continuously revised. It grew from this snippet, and is still growing as I find things I use often.
Presently, libNog features:

A way to browser-independently get an XMLHttpRequest object.
A set of simple methods for GET, POST, HEAD, and to include other Scripts.
Simple methods for className control
A completely abstracted form of getElement*
Browser-independent methods for attaching and detaching event handlers
An event-normalization routine
A simple one-command 'Stop the Event' routine
And the big one: A simplified Class object by which classes can be built in JavaScript.

The above link will point you to the API documentation and history of libNog, as well as where to download the library.

Convert
java.awt.Canvas to java.awt.image.BufferedImage or java.awt.image.Image

From a tutorial on building an RSS SAX parser on my website:

full article can be found here

Snippet for display one frame in full screen mode.

Convert java.awt.Canvas to java.awt.image.BufferedImage

Convert InputStream to byte[]

A simple, yet powerful (what a cliché) way of resgistering javascript keyboard shortcuts. Register any kind of keyboard shortcuts, and if applicable, override the browser default action.

Example usage and more info here:

Javascript Keyboard Shortcut Manager

Search file directory (recursive method) with java language

A quick implementation of an encrypter which can't be cracked by frequency analysis.

The decrypter for the simple encrypter I posted earlier - Takes the encrypted text from a text file - "encrypt.txt" which the encrypter automatically writes to.