This is a simple script to provide basic cross-platform XML request functionality in Javascript. It's meant to be the core component in any AJAX style framework. It is not an instantiable object, but instead is a namespaced microlibrary.

Calling is easy:
XMLRequest.GET(uri, query, callback, fallback)
uri: The location you're after
query: an associative array of form data to provide via the URL
callback: callback function of the form myCallbackFunction(objXMLHttpRequest), which is called upon successful (response = 200 OK) retrieval of the XML data
fallback: myFallbackFunction(objXMLHttpRequest), which is called upon failed (response != 200 OK) retrieval of the XML data.

XMLRequest.POST(uri, query, form, callback, fallback)
Similar, but does the query using the POST method. 'query' is the URL-appended data, still in associative array form, and 'form' is the same for the POST data.

Generates a tree view within a dropdown select box.

Not really a hack, but rather a workaround for layout problems with IE.
Conditional

List all plugins installed in FF

Get computed Height of an HTML Element

Flexible sorting algorithm based on Quicksort with extra functionality, such as:
- Direction (ie: ascending or descending)
- Sort-by-path (eg: item.name, item.name.firstName or item[5])
- Sorting function (returns true if two items are already sorted)
- Type checking
- All constants and support functions are members of the Sort() function
- Testsuite with hooks for cscript and in-browser javascript, so you can tweak and optimize, and make sure it still works
- Environment agnostic (can use with, say, SpiderMonkey or .Net's jsc)

Here's a library to manage CSS class names on DOM elements.

Simple chatting script to be placed on a corner of a website
Also a good example how to use ajax.

Here's a basic function for debugging any kind of PHP variable. It allows for "invisible" or "visible" output--that is output in HTML comments or within visible HTML tags. It also supports customizable "containers" which lets you easily edit the look of the visible and invisible blocks. Examples in code below.

Set a word or phrase in an input field, clear it onfocus