Proto.Menu is a simple and lightweight (approximately 3KB only) prototype-based solution that will allow you to create your own context menu. Proto.Menu is very easy to use and fully customizable through CSS. It has been thoroughly tested and features extensive set of unit tests to ensure expected behavior.
Proto.Menu is unobtrusive and uses its own namespace. It is cross-browser and fully support all A-grade browsers (Opera is supported through Ctrl + Left Click). Not only it is lightweight, it also renders really fast; Menu container is rendered on page load, and only changes position when rendered (on click event).
Developed by Juriy Zaytsev; Proto.Menu is released under MIT license. You can find further information, demo & download on Proto.Menu Website.