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Raphaël is a small JavaScript library that should simplify your work with vector graphics on the web. If you want to create your own specific chart or image crop and rotate widget, for example, you can achieve it simply and easily with this library.

Skulpt is an entirely in-browser implementation of Python.

Narwhal is a cross-platform, multi-interpreter, general purpose JavaScript platform. It aims to provide a solid foundation for building JavaScript applications, primarily outside the web browser. Narwhal includes a package manager, module system, and standard library for multiple JavaScript interpreters.

JSON Template is a minimal but powerful templating language, currently implemented in both Python and JavaScript.

Flot is a pure Javascript plotting library for jQuery. It produces graphical plots of arbitrary datasets on-the-fly client-side.

SelectorGadget is an open source bookmarklet that makes CSS selector generation and discovery on complicated sites a breeze. Just drag the bookmarklet to your bookmark bar, then go to any page and press it. A box will open in the bottom right of the website. Click on a page element that you would like your selector to match (it will turn green). SelectorGadget will then generate a minimal CSS selector for that element, and will highlight (yellow) everything that is matched by the selector. Now click on a highlighted element to remove it from the selector (red), or click on an unhighlighted element to add it to the selector. Through this process of selection and rejection, SelectorGadget helps you come up with the perfect CSS selector for your needs.

MobWrite converts forms and web applications into collaborative environments. Create a simple single-user system, add one line of JavaScript, and instantly get a collaborative system.

MooTools is 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.

Jash is a DHTML-based window that gives you command-line JavaScript access to the current browser window. With this console you can quickly debug scripts, manipulate the DOM, view the current page's objects, functions, and variables, trace the execution stack, execute arbitrary Javascript, enter new CSS (in IE, Firefox, Opera, and Safari), and much more.

Highlight.js highlights syntax in code examples on blogs, forums and in fact on any web pages. It's very easy to use because it works automatically: finds blocks of code, detects a language, highlights it.

Ext Javascript library howto

add reflections to images on webpages through javascript

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JavaScript Archive Network

AJAX library