my line dot background

Yesterday I build a page to use a canvas as background full of dots and lines. And the screenshot is something below:

And I put it in my github.Feel free to use it or change it.

The most difficult part is cleaning the previous drawing. Thanks for the help come from stackoverflow, which let me know the composition of canvas.

References:

1. html5-canvas-clear-arc-method
2. Drawing shapes with canvas
3. Compositing and clipping
4. ECMAScript 6 — New Features: Overview & Comparison