Shows hours:minutes:seconds.milliseconds using requestAnimationFrame().
Note that this code runs slow on Chrome 47 on Linux on Intel video card on my laptop. It seems that painting the text is too slow in this system.
However, it works fine and fast on Chrome 47 on Windows on Nvidia video card on my desktop.
I've also posted this to https://github.com/denilsonsa/denilsonsa.github.io/commit/6a751b4cad91a154659dc5a6382f76c50c54cce6 or http://denilson.sa.nom.br/clock.html
A Pen by Denilson Figueiredo de Sá on CodePen.