This is an example of ar.js with a-frame. Less than 10lines of html and you get augmented reality!!!
Put an image of hiro marker in front of the camera. It will open a webpage which read the phone webcam, localize a hiro marker and add 3d on top of it, as you can see below. It has never been easier :)
Checkout AR.js - Efficient Augmented Reality for the Web.