Matthew

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>Alg 4 - moving a line with mouse</title>
</head>

<body>

<canvas id="myCanvas" width="640" height="480" style="boarder:1px solid black";>
</canvas>

<script>

var canvas = document.getElementById("myCanvas");
var dt =canvas.getContext("2d");

     var radGrd = dt.createRadialGradient(320, 250, 30, 350, 260, 300);
    radGrd.addColorStop(1,"#fff");
    radGrd.addColorStop(0,"#f00");

    dt.fillStyle = radGrd;
    dt.fillRect(0,0,640,480);

 document.addEventListener("mousemove", lineDraw);

function lineDraw()
{
   dt.clearRect(0,0,640,480);
    dt.beginPath();
    dt.arc(event.clientX,event.clientY,100,0,2*Math.PI);
    dt.stroke();
    dt.fill();
}


</script>
</body>

</html>