<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>绘制渐变图形</title>
<script>
function draw(id){
var canvas=document.getElementById(id);
var context=canvas.getContext("2d");
var g1=context.createLinearGradient(0,0,0,300);
g1.addColorStop(0,"rgb(255,255,0)");//开始的颜色
g1.addColorStop(1,"rgb(0,255,255)");//结束的颜色
content.fillStyle=g1;//填充颜色
content.fillRect(0,0,500,500);
//以上绘制矩形 渐变
//以下绘制圆形渐变
var g2=context.createLinearGradient(0,0,300,0);
g2.addColorStop(0,"rgba(0,0,255,0.5)");
g2.addColorStop(1,"rgba(255,0,0,0.5)");
for(var i=0;i<10;i++){
content.beginPath();
context.fillStyle=g2;
context.arc(i*25,i*25,i*10,0,Math.PI*2,true);//圆形
context.close();
context.fill();
}
}
</script>
</head>
<body onload="draw("canvas");">
<canvas id="canvas" width="500" height="500"></canvas>
</body>
</html>