这里主要是应用了一个rainyday的js类库，使用非常简单方便，就不多废话了，看演示代码吧。
<!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">
<style media="screen">
body {
overflow: hidden;
height: 100%;
margin: 0;
padding: 0;
}
img {
width: 100%;
height: 100%;
}
</style>
<script src="http://maroslaw.github.io/rainyday.js/dist/rainyday.0.1.2.min.js" type="text/javascript"></script>
<script type="text/javascript">
function run() {
var image = document.getElementById('background');
image.onload = function() {
var engine = new RainyDay({
image : this,
});
engine.rain([ [ 1, 2, 8000 ] ]);
engine.rain([ [ 3, 3, 0.88 ], [ 5, 5, 0.9 ], [ 6, 2, 1 ] ], 100);
}
image.crossOrigin = 'anonymous';
image.src = 'http://i.imgur.com/N7ETzFO.jpg';
}
</script>
<title>哇塞！</title>
</head>
<body onLoad="run();">
<img id="background" alt="background" src="" />
</body>
</html>
是不是非常酷的效果呢？希望大家能够喜欢。