A simple JavaScript shopping cart in under 20kb that you can setup in minutes. It's lightweight, fast, simple to use, and completely customizable. All you need to know is basic HTML.

This extension implements the JavaScript Object Notation (JSON) data interchange format. The decoding is handled by a parser.

A JavaScript framework that aims to ease development of dynamic web applications. Features a unique, easy-to-use toolkit for class-driven development and the nicest Ajax library around. A codebase of choice for web application developers everywhere.

A full-featured open source solution designed for Ajax Push. It includes a Comet server and a Javascript framework. APE allows to implement any kind of real-time data streaming to a Web browser, without having to install anything on the client-side.

A free and open source jQuery HTML5 audio/video media library written in JavaScript. Create innovative media solutions with featured such as totally customizable and skinnable using HTML and CSS, free plugins, multi-codec, cross-browser and ...

A compact, modular, object-oriented JavaScript framework designed for the intermediate to advanced JavaScript developer. It allows you to write powerful, flexible, and cross-browser code with its elegant, well documented, and coherent API.

JsFiddle is a playground for web developers. One can use it as an online editor for snippets build from HTML, CSS and JavaScript. The code can then be shared with others, embedded on a blog, etc. We aim to support all actively developed frameworks.

A professional frontend developers's base HTML/CSS/JS template for a fast, robust and future-safe site. Cross-browser normalization, performance optimizations, even optional features like cross-domain XHR and Flash.

Queness is a hybrid of weblog and online community with heaps of design inspirations and great collection of JavaScript and jQuery tutorials.

Let's examine a few examples of how multiple select fields can be implemented in HTML and PHP (as well as some JavaScript).