A small example (from when I was learning to use canvas and now tarted up a little) of drawing circles on a canvas. The colours have an alpha channel,
for example: rgba(255,0,0,0.5). The dashed canvas border is just some CSS that I've applied to the canvas tag to make it easily
identifiable. A far better example of the canvas tag is my canvas based graphing library:
RGraph. I was going to add the source code, but as I added
animation it grew somewhat. So now you'll simply have to view the source (life is so hard isn't it...?).
Note
By forcing IE9 into HTML5 mode and adding lots of balls, you'll be able to really see the speed advantage it has over other browsers due to hardware acceleration.