JS Canvas Radnom Circle Gen V1

<html>
<body onload="var intt=prompt('Enter Amount Of Circles Gen:');
for(var i=0;i<intt;i++){
Draw();
}">
<canvas id="myCanvas" width="1000" height="1000"
style="border:0px solid #d3d3d3;">
Your browser does not support the canvas element.
</canvas>
<script>
function Draw(){
var canvas = document.getElementById("myCanvas");
var ctx=canvas.getContext("2d");
ctx.border='1px';
ctx.fillAlign = "center";
ctx.beginPath();
ctx.fillStyle='magenta';
ctx.arc(Math.random()*1000,Math.random()*1000,40,0,2*Math.PI);
ctx.fill();
}
</script>
</body>
</html>