Draw with your mouse by clicking, holding down and dragging…
I often use some variation of this depending on the project… This snippet normalizes touch events in a simple way, prevents scrolling and gives an example of how to handle multi-touch.
You’ll probably want a to use a meta tag like this – for the full effect.
<meta name="viewport" content="width=device-width, initial-scale=1.0">
See more stuff like this over @ Snippet Zone