<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>渐变的矩形</title>
<script>
window.onload = function(){
var c = document.getElementById('c');
var ctx = c.getContext('2d');
//创建线型渐变对象
var jb = ctx.createLinearGradient(0,0,200,0);
jb.addColorStop(0,'red');
jb.addColorStop(.25,'green');
jb.addColorStop(.5,'orange');
jb.addColorStop(1,'blue');
ctx.fillStyle = jb;
ctx.fillRect(0,0,200,100); //x起点, y起点, x终点， y终点
}
</script>
</head>
<body>
<canvas id="c" width="400" height="400" ></canvas>
</body>
</html>
