VNC.js is a LinkedIn intern hackday 2011 2011 project, read the blog post about VNC.js: http://engineering.linkedin.com/javascript/vncjs-how-build-javascript-vnc-client-24-hour-hackday
You need a VNC server to make this work, like: x11vnc on Ubuntu.
This project was developed over 24 sleep deprived hours, the code is messy and undocumented.