html5 指定位置、颜色在canvas上绘制圆形图案
<!DOCTYPE html>
<html>
<body>
<canvas id="myCanvas" width="200" height="100" style="border:1px solid #c3c3c3;">
Your browser does not support the HTML5 canvas tag.
</canvas>
<script type="text/javascript">
var c=document.getElementById("myCanvas");
var ctx=c.getContext("2d");
ctx.fillStyle="#FF0000";
ctx.beginPath();
ctx.arc(70,18,15,0,Math.PI*2,true);
ctx.closePath();
ctx.fill();
</script>
</body>
</html>
