<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>径向渐变图形</title>
</head>
<body>
<canvas id="canvas" width="400" height="300" style="border:1px solid blue;"></canvas>
<script>
var c=document.getElementById('canvas');
var cxt=c.getContext("2d");
var grd=cxt.createRadialGradient(200,150,0,200,150,150);
grd.addColorStop(0,"#fff");
grd.addColorStop(1,"#000");
cxt.fillStyle=grd;
cxt.fillRect(0,0,400,300);//绘制矩形
</script>
</body>
</html>
