In their own words tracking.js “brings different computer vision algorithms and techniques into the browser environment.” all you need to do is to download a file of 7B that includes all the tracking.js examples, source code dependencies and many more.
Download and Demo
Face Recognition API
It was designed by Jay salvat. This one uses the algorithm by Lui Lui for face detection. Face is detected from images, videos and canvases as well to receive there coordinate. It includes a set of examples and result analysis as well.
Face Detection JS
This one was designed by Paul Viola and Rainer Lienhart. It supports its use in IE 9+, Safari and Opera Mobile but not in iso and explorer. Along with face detection it allows tracking and, in combination with modern HTML5.