scriptaculous
script.aculo.us is an open-source JavaScript framework
...It builds on the Prototype JavaScript library and adds higher-level tools for animation, drag-and-drop behavior, controls, sliders, and interface enhancements. The project was created for websites that wanted richer user interaction before modern frontend frameworks became common. Developers could include Prototype and the script.aculo.us files, then use the provided modules to create dynamic page behavior. The repository includes source files, library builds, tests, examples, and installation guidance. It is most useful today as a legacy frontend dependency, a historical reference, or a maintenance tool for older Prototype-based applications.