Browse free open source JavaScript Libraries and projects below. Use the toggles on the left to filter open source JavaScript Libraries by OS, license, language, programming language, and project status.

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  • 1
    gray-matter

    gray-matter

    Smarter YAML front matter parser

    gray-matter is a JavaScript library for parsing front matter from strings or files. It is commonly used in static site generators, documentation systems, content pipelines, and Markdown-based publishing tools. The library parses YAML front matter by default, but it can also work with JSON, TOML, CoffeeScript-style front matter, and custom parsers. It returns the content body and extracted metadata as a structured object that applications can process easily. Its parser is designed to be faster and more reliable than simple regular-expression approaches, especially around edge cases. It is useful whenever developers need clean metadata extraction from Markdown, HTML, or other text-based content files.
    Downloads: 0 This Week
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  • 2
    gremlins.js

    gremlins.js

    Monkey testing library for web apps and Node.js

    Gremlins.js is an open-source monkey testing library written in JavaScript. It unleashes a horde of undisciplined gremlins on a web app in order to check its robustness. We've modernized the code of Gremlins.js, our monkey testing library for frontend apps. It's now super easy to detect memory leaks in your JavaScript code. Gremlins.js comes with 5 types of undisciplined gremlins that will try to break your web application: the clicker, the form filler, the scroller, the typer and the toucher. You can also add custom gremlins easily. While gremlins try their best to destroy your app, another type of scripts called mogwais monitor the console errors and the number of frames by second to detect performance problems. Every action performed by the gremlins, and all the errors that might occur, are all logged! In version 2.0, we now use npm to publish the library and unpkg to serve it!
    Downloads: 0 This Week
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  • 3
    HTML5 canvas chart library (javascript) . Display and animate charts & graph in HTML5 Canvas. Signal,pie,ring,led,digital,odometer, radial and lineal meters, thermometer and vumeter,piramid,funnel,stack and Multiserie charts availables
    Downloads: 0 This Week
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  • 4
    heatmap.js

    heatmap.js

    JavaScript Library for HTML5 canvas based heatmaps

    heatmap.js is a lightweight, easy to use JavaScript library to help you visualize your three dimensional data! Use it to add new value to your project, build a business based on it, study and visualize user behaviour, or why not build something completely crazy/awesome? Whether you want to have an aggregated overview of your users behaviour, or look at thousands of events distributed on a map, heatmap.js has all your heatmap visualization needs covered! Because it is the most advanced heat map visualization library on the web. It has a light footprint (~3kB gzip) and with the new 2.0 release heatmap.js just got faster and better. With only a few lines of code you can create your own interactive web heatmap. heatmap.js' API is all documented, also prioritized, so you can start developing right away! Heatmap.js is not a user behaviour tracking script. It simply creates dynamic heatmaps based on the data you feed it.
    Downloads: 0 This Week
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  • 5
    hello.js

    hello.js

    API library for connecting with OAuth2 services

    A client-side JavaScript SDK for authenticating with OAuth2 (and OAuth1 with an OAuth proxy) web services and querying their REST APIs. HelloJS standardizes paths and responses to common APIs like Google Data Services, Facebook Graph and Windows Live Connect. It’s modular, so that list is growing. No more spaghetti code! Compiled source, which combines all of the modules, can be obtained from GitHub, and source files can be found in Source. The Bower package shall install the aforementioned "/src" and "/dist" directories. The "/src" directory provides individual modules which can be packaged as desired. If a network string is provided: A consent window to authenticate with that network will be initiated. Else if no network is provided a prompt to select one of the networks will open. A callback will be executed if the user authenticates and or cancels the authentication flow.
    Downloads: 0 This Week
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  • 6
    history

    history

    Manage session history with JavaScript

    The history library lets you easily manage session history anywhere JavaScript runs. A history object abstracts away the differences in various environments and provides a minimal API that lets you manage the history stack, navigate, and persist state between sessions. Development of the current stable release, version 5, happens on the master branch. Please keep in mind that this branch may include some work that has not yet been published as part of an official release. However, since master is always stable, you should feel free to build your own working release straight from master at any time. history is developed and maintained by React Training. If you're interested in learning more about what React can do for your company, please get in touch!
    Downloads: 0 This Week
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  • 7

    hummingbird

    The most sensible component system for Tailwind.

    Hummingbird is a component system for Tailwind developers who care about architectural discipline. It ensures global design control with local utility flexibility. Hummingbird is a lightweight, framework-agnostic tool that integrates seamlessly with modern stacks and helps build scalable, maintainable web applications without extra weight.
    Downloads: 0 This Week
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  • 8
    i18n-locales

    i18n-locales

    List of locales for i18n

    List of locales for i18n.
    Downloads: 0 This Week
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  • 9
    iCSS

    iCSS

    More than CSS

    iCSS is a large curated repository of advanced CSS techniques, creative experiments, and deep dives into modern web animation and styling capabilities. Rather than being a traditional library, the project functions as an educational and inspirational knowledge base that explores unusual, powerful, or overlooked CSS features. The content covers topics such as layout tricks, animation patterns, visual effects, accessibility considerations, and emerging CSS standards. Materials are continuously updated and organized by category, helping frontend developers discover new approaches to solving UI and visual design challenges. The repository aims to broaden developers’ thinking about what can be achieved purely with CSS and native browser capabilities. Overall, iCSS serves as a high-value reference and inspiration hub for frontend engineers seeking to push the boundaries of modern CSS.
    Downloads: 0 This Week
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  • 10
    iView Weapp

    iView Weapp

    A set of high-quality WeChat applet UI component library

    Use WeChat to scan and experience the example of small program components. Before you start using iView Weapp, you need to read the micro-channel applet custom components related documents. We have built-in examples of all components, you can scan the small program code experience on the right, or view it in WeChat developer tools. Then, the examplesdirectory can be opened in the micro-channel developer tools. We adopted a 24-grid system to divide the area into 24 equal parts, which can easily deal with most layout problems. Using the grid system for web page layout can make the page layout beautiful and comfortable. The grid contains 4 components: i-grid, i-grid-item, i-grid-icon, i-grid-label, among them, i-grid-icon and i-grid-label have customized styles by default, but These two components can also be eliminated in development.
    Downloads: 0 This Week
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  • 11
    image-to-ascii

    image-to-ascii

    A Node.js module that converts images to ASCII art

    image-to-ascii is a Node.js module that converts raster images into character-based terminal artwork. Input can come from a local file, remote URL, or in-memory Buffer. The converter maps pixel brightness to a configurable sequence of ASCII characters. It can preserve the original colors through ANSI foreground or background styles or generate plain monochrome output. Options control width, height, screen fitting, aspect ratio, transparency, reversed brightness, and custom background colors. Developers can receive a final string or work with the underlying pixel matrix through custom processing functions. A companion command-line package and webcam example provide additional ways to use the conversion engine.
    Downloads: 0 This Week
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  • 12
    interview-ouch

    interview-ouch

    Simple web snippets for interviews

    interview-ouch is a cheeky, realistic collection of tough interview questions and scenarios that tend to “hurt” unprepared candidates. It’s meant to expose the gaps in typical interview prep by highlighting non-trivial, edge-case, or context-heavy questions. The repo covers programming, systems, and sometimes softer judgment questions that interviewers use to see how you think under pressure. Instead of focusing only on textbook algorithms, it nudges you toward understanding trade-offs, code quality, debugging, and real-world constraints. This makes it a good practice tool for senior or experienced candidates who won’t be impressed by just LeetCode-style prompts. It’s also helpful for interviewers who want to refresh their own question bank with more challenging material.
    Downloads: 0 This Week
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  • 13
    Javascript library assisting in measuring the IP protocol webclients are using (IPv4, IPv6) and assessing broken webclients when websites go dual stack.
    Downloads: 0 This Week
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  • 14
    ipynb-quicklook

    ipynb-quicklook

    Generator for Jupyter/IPython notebooks without further dependencies

    A Quick Look generator for Jupyter/IPython notebooks without further dependencies. This plugin has now been integrated into a native macOS app, Jupyter Notebook Viewer. This is the recommended way to install the QuickLook generator. A stand-alone Quick Look generator for Jupyter/IPython notebooks on macOS. Contents are rendered on-the-fly using nbviewer.js.
    Downloads: 0 This Week
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  • 15

    ismp

    This project has moved to github

    This project has moved to github
    Downloads: 0 This Week
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  • 16
    isomerjs

    isomerjs

    Simple isometric graphics library for HTML5 canvas

    Isomer is a lightweight JavaScript library for drawing isometric scenes on an HTML5 canvas. It provides abstractions for points, vectors, paths, shapes, colors, and the complete rendering surface. Built-in shape helpers create prisms, pyramids, and cylinders, while extrusion turns two-dimensional paths into three-dimensional objects. Shapes can be translated, scaled, or rotated around the X, Y, and Z axes. The renderer orders surfaces by depth to reduce visual overlap problems when drawing complex scenes. Developers can combine custom paths and colors to construct buildings, diagrams, game graphics, and procedural illustrations. The library can be added directly through a script file and requires no dedicated 3D rendering engine.
    Downloads: 0 This Week
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  • 17
    isomorphic-fetch

    isomorphic-fetch

    Isomorphic WHATWG Fetch API, for Node and Browserify

    Fetch for node and Browserify. Built on top of GitHub's WHATWG Fetch polyfill. For ease-of-maintenance and backward-compatibility reasons, this library will always be a polyfill. As a "safe" alternative, which does not modify the global, consider fetch-ponyfill. The Fetch API is currently not implemented consistently across browsers. This module will enable you to use fetch in your Node code in a cross-browser compliant fashion. The Fetch API is part of the Web platform API defined by the standards bodies WHATWG and W3C. All open source code released by FT Labs is licenced under the MIT licence. Based on the fine work by jxck.
    Downloads: 0 This Week
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  • 18
    iziModal

    iziModal

    Elegant, responsive, flexible and lightweight modal plugin with jQuery

    Elegant, responsive, flexible and lightweight modal plugin with jQuery. All modern browsers are supported (Tested in Chrome, Firefox, Opera, Safari, IE9+ and Edge).
    Downloads: 0 This Week
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  • 19
    jAjaxLib is a Javascript library for simplyfing the use of Ajax. It is focused on simplicity and has a very shallow and fast learning curve.
    Downloads: 0 This Week
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  • 20
    jCanvas

    jCanvas

    A jQuery plugin that makes the HTML5 canvas easy to work with

    jCanvas is a jQuery plugin that makes the HTML5 canvas easy to work with. jCanvas is a JavaScript library, written using jQuery and for jQuery, that wraps around the HTML5 canvas API, adding new features and capabilities, many of which are customizable. Capabilities include layers, events, drag-and-drop, animation, and much more. The result is a flexible API wrapped up in a sugary, jQuery-esque syntax that brings power and ease to the HTML5 canvas.
    Downloads: 0 This Week
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  • 21
    jCarousel

    jCarousel

    Riding carousels with jQuery

    jCarousel is a jQuery plugin for controlling a list of items in horizontal or vertical order. It provides a full-featured and flexible toolset for navigating any HTML-based content in a carousel-like fashion.
    Downloads: 0 This Week
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  • 22
    jIceTabset is a tabset jQuery plugin
    Downloads: 0 This Week
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  • 23
    jQ-Windows

    jQ-Windows

    jQ-Windows is a jQuery based window manager

    jQ-Windows is a jQuery based window manager component which can be used in web applications. The user interface easily integrates with the jQuery-UI library. There is no public release yet, although there is a development release available for download.
    Downloads: 0 This Week
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  • 24
    jQuery & Zepto Lazy

    jQuery & Zepto Lazy

    A lightweight, fast, feature-rich, powerful and highly configurable

    Lazy is a fast, feature-rich, and lightweight delayed content-loading plugin for jQuery and Zepto. It's designed to speed up page loading times and decrease traffic to your users by only loading the content in view. You can use Lazy in all vertical and horizontal scroll ways. It supports images in img / tags and backgrounds, supplied with CSS like background-image, by default. On those elements, Lazy can set a default image or a placeholder while loading and supports retina displays as well. But Lazy is even able to load any other content you want by plugins and custom loaders.
    Downloads: 0 This Week
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  • 25
    jQuery Bootstrap-style Dropdowns

    jQuery Bootstrap-style Dropdowns

    Bootstrap-style dropdowns with some added features and no dependencies

    Bootstrap-style dropdowns with some added features and no dependencies.
    Downloads: 0 This Week
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