<html>
<script language=javascript>
function draw() {
var canv = document.getElementById("canv");
var ctx = canv.getContext("2d");
try {
canv.width = 50000;
} catch (e) { }
ctx.clearRect(0, 0, 10, 10);
}
</script>
<body onload="draw()">
<canvas id="canv" width="5" height="5"></canvas>
</body>
</html>