JS Random Rect Drawing SRC V1

<!DOCTYPE html>
<html>
<body>

<canvas id="myCanvas" width="500" height="500"
style="border:1px solid #c3c3c3;">
Your browser does not support the canvas element.
</canvas>

<script>
var i=prompt("Enter # Of Times To Scramble Canvas:");
for(var i1=0;i1!=i;i1++){
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.fillStyle = "#FF0000";
ctx.fillRect(Math.random()*100,Math.random()*100,Math.random()*100,Math.random()*100);
}
</script>

</body>
</html>