Is it possible to have a full screen canvas element in the background of a webpage and "normal" markup elements like a table in front of it?
like the following snippet (if it wouldn't be used as alternative content):
<canvas id="imageView" width=100%; height=100%;>
<table>...</table>
</canvas>
You could try setting a CSS style on the canvas where it has a position: fixed (or absolute as appropriate), and then any content that follows it (as opposed to container content as you've given in your example) should sit on top of it.
I tried it for you with the following code. The div gets placed on top of the canvas element just as Matthew describes it. So should work for you
<!DOCTYPE HTML>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Canvas demo</title>
<style type="text/css">
#canvasSection{ position:fixed;}
</style>
<script type="text/javascript">
function draw()
{
//paint the text
var canvas = document.getElementById('canvasSection');
var context = canvas.getContext('2d');
context.fillStyle = '#00f';
context.font = 'italic 30px sans-serif';
context.textBaseline = 'top';
context.font = 'bold 30px sans-serif';
context.strokeText('Your Text!!', 0, 0);
//paint the square
var canvasSquare = document.getElementById('canvasSquare');
var ctxSquare = canvas.getContext('2d');
ctxSquare.fillStyle='#FF0000';
ctxSquare.fillRect(0, 100,50,100);
}
</script>
</head>
<body onLoad="draw()">
<canvas id="canvasSection">Error, canvas is not supported</canvas>
<div>TestText</div>
</body>
</html>
You can't yet do this in normal HTML5 without hacky positioning stuff, but Webkit-based browsers do allow you to use a element in the CSS background property. Just give the canvas an id, then use body { background:url(#mycanvas); } in your CSS.