canvas background demo

<!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;
      top:0;
      left:0;
     }
</style>
<script type="text/javascript">
function draw()
{
var canvas = document.getElementById('canvasSection');
var ctxSquare = canvas.getContext('2d');
ctxSquare.fillStyle='#999999';
ctxSquare.fillRect(0, 0,30,30);
}
</script>
</head>
<body onLoad="draw()">
<canvas id="canvasSection">Error, canvas is not supported</canvas>
<div style="z-index:1">TestText</div>
</body>
</html>