<!DOCTYPE html><head>
<meta charset=utf-8>
<title>HTML5画线、圆、矩形</title>
<script src="<a href="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script">http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script</a>>
</head>
<script>
$(document).ready(function(){
var c=document.getElementById("drawbox");
var draw=c.getContext("2d"); //获取2d内容的引用，调用绘图API</p>
<p>//指定渐变区块
var grd=draw.createLinearGradient(50,50,200,50); //坐标，长宽
grd.addColorStop(0,"black"); //起点颜色
grd.addColorStop(1,"green"); //终点颜色</p>
<p>draw.fillStyle=grd; //设为填充样式
draw.fillRect(50,50,200,50); //填充进矩形内
})
</script>
</body>
<canvas id="drawbox" width="500" height="500"></canvas>
</body>
</html>
效果图：
