Javascript Toolbox is a repository of code and reusable libraries which address common needs that many web developers encounter. The code found here is based on standards but also tries to be backwards-compatible for browsers which don’t support the standards. All code on the site is written by one person, in a consistent fashion, tested thoroughly, and used in practice by thousands of web sites around the world.

Dynamic Drive is a place on the net to obtain free, original DHTML & Javascripts to enhance your web site. The site is regularly updated.

Code Snippets is a public source code repository. It allows to easily build up your personal collection of code snippets, categorize them with tags / keywords, and share them with the world.

Bajax is a very small and simple javascript library to use Ajax on your pages. It is independent of programming language. You can put dynamic content using simple commands.

ATLAS is  free framework for quickly creating a new generation of more efficient and interactive Web experiences that work across all the most popular browsers. With ASP.NET AJAX you can create next-generation interfaces with reusable AJAX components, enhance existing pages using powerful AJAX controls with support for all modern browsers. Continue using Visual Studio 2005 to take your ASP.NET 2.0 sites to the next level. Access remote services and data from the browser without tons of complicated script.

AjaxRequest Library   is a layer over the XMLHttpRequest functionality which makes the communication between Javascript and the server easier for developers. It makes the interface more logical and consistent with what developers expect. It supports multiple simultaneous requests which will not collide with each other without any additional work from the developer.

Ajax.NET Professional is one of the first AJAX frameworks available for Microsoft ASP.NET and is working with .NET 1.1 and 2.0. You can find here a quick guide how to get the first Ajax.NET method running.

AjaxAC is an open-source framework written in PHP, used to develop/create/generate AJAX applications. The fundamental idea behind AJAX (Asynchronous JavaScript And XML) is to use the XMLHttpRequest object to change a web page state using background HTTP sub-requests without reloading the entire page. It is released under the terms of the Apache License v2.0.

dojo   is an Open Source DHTML toolkit written in JavaScript. It builds on several contributed code bases (nWidgets, Burstlib, f(m)), which is why we refer to it sometimes as a “unified” toolkit. Dojo aims to solve some long-standing historical problems with DHTML which prevented mass adoption of dynamic web application development. It allows you to easily build dynamic capabilities into web pages and any other environment that supports JavaScript sanely. You can use the components that Dojo provides to make your web sites more usable, responsive, and functional.

AHAH is a very simple technique for dynamically updating web pages using JavaScript . It involves using XMLHTTPRequest  to retrieve (X)HTML  fragments which are then inserted directly into the web page, whence they can be styled using CSS. it is a subset with some very specific and useful properties, such as the lack of custom XML schemas. AHAH can trivially reuse existing HTML pages, avoiding the need for a custom web service. All data transport is done via browser-friendly HTML, easing debugging and testing. The HTML is designed to be directly embedded in the page’s DOM, eliminating the need for parsing.