Placing a <div> within a <canvas>
You cannot place elements inside a canvas (and have both displayed); they are only displayed if the browser does not understand the canvas element.
If you would like to position elements over the same area as a canvas, here is one technique (among many) that would let you do it:
HTML
<div id="canvas-wrap">
<canvas width="800" height="600"></canvas>
<div id="overlay"></div>
</div>
CSS
#canvas-wrap { position:relative } /* Make this a positioned parent */
#overlay { position:absolute; top:20px; left:30px; }
Here's another technique, which lets the content of the div flow normally and makes the canvas a background to the content:
CSS
#canvas-wrap { position:relative; width:800px; height:600px }
#canvas-wrap canvas { position:absolute; top:0; left:0; z-index:0 }