JS+HTML5 Canvas实现线性渐变效果

<!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");
var grd=ctx.createLinearGradient(0,0,175,50);
grd.addColorStop(0,"#FF0000");
grd.addColorStop(1,"#00FF00");
ctx.fillStyle=grd;
ctx.fillRect(0,0,175,50);
</script>
</body>
</html>