ControlP5 (www.sojamo.de/libraries/controlP5) is a library written by Andreas Schlegel for the programming environment processing. ControlP5 is a GUI and controller library for processing that can be used in authoring, application mode. Controllers including Sliders, Buttons, Toggles, Knobs, Textfields, RadioButtons, Checkboxes amongst others can be easily added to a processing sketch and can be arranged in separate control windows, or can be organized in tabs or groups. The controlP5 source code repository is available on github at github.com/sojamo/controlp5.
Currently there is no javascript version of ControlP5, though I had started implementing a slimmed down version for processing.js but since it is currently unclear which javascript version, processing.js or p5.js, will become the default js version of processing, controlP5.js is on hold.