A key new element in HTML5 is the canvas. This allows drawing graphics in Javascript as one can through say the 2D graphics API available in Java for instance.

In Card 2013 I'm using the HTML5 Canvas for the hint meter (on the hidden object scenes it's at the right hand end of the status bar at the bottom). In particular for drawing the circle showing how the hint meter is recharging. And also for drawing the circles when the hint meter is pressed.

Perhaps I could use the canvas alone rather than the mix of HTML4 elements like IMG and DIV and TD that I do use. Not sure. But the canvas element enables adhoc drawing which it wouldn't be possible otherwise to do.