This is the Visualization Tool used for CS 1332 which covers all data structures & algorithms taught in class. It is hosted using Github Pages, and you can visit it at: https://rodrigodlpontes.github.io/visualization-tool/.
This tool is based on the already excellent website by David Galles. His code was written about 10 years ago, so it doesn't use more modern JavaScript syntax (much can be improved in that aspect).
Like any other website/web app, there are three main components to the Visualization Tool: HTML, JavaScript and CSS.
HTML files are in the root directory. As usual, there is an index.html which is the initial page of the app, and an about.html with more information about the project.
For each data structure/algorithm page, there is a corresponding HTML file (e.g. ArrayList.html). These are pretty much copies of each other, with corresponding headers and references to JavaScript files changed.
This is the bulk of the project, containing all the logic for the animations. Files are mostly located under AlgorithmLibrary and AnimationLibrary.
AlgorithmLibrary contains all the scripts for data structures/algorithms, so most of the work will be done there.
AnimationLibrary contains the logic for the underlying animations (the API, in a sense), and will (for the most part) not need to be modified.
visualPages.css styles the "regular" index.html and about.html pages, and visualizationPageStyle.css styles data structure/algorithm pages.
The animations "API" is very well documented here. Existing JavaScript files are also a good reference for learning how to do things.
There is a lot that still needs to be improved, ranging from implementing a few remaining data structures/algorithms, making slight modifications to existing ones, bug fixing, updating the UI and making general improvements. Whatever your interest in web development is, you can probably improve your skills by contributing in that regard.
For more details on what needs to be done, check out the Projects page. What is outlined there is just to help guide development though, so feel free to contribute with whatever you think would be useful.