<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Glunefish</title>
<link rel="stylesheet" href="css/style.css">
<style>
* {
margin: 0; padding: 0; border: none; outline: 0;
}
body{
width: 100vw;
height: 100vh;
background: url(img/bg.png) no-repeat;
background-size: cover;
}
#F-dynamicbg-box {
width: 100vw;
height: 100vh;
position: absolute;
top: 0;
left: 0;
overflow: hidden;
}
#F-dynamicbg-box > div {
z-index: -9999;
background-color: rgba(255,255,255,.1);
position: absolute;
top: 105vh;
animation: dynamicDiv 30s linear infinite;
}
#F-dynamicbg-box > div:nth-of-type(1) { animation-delay: 1s }
#F-dynamicbg-box > div:nth-of-type(2) { animation-delay: 3s }
#F-dynamicbg-box > div:nth-of-type(3) { animation-delay: 6s }
#F-dynamicbg-box > div:nth-of-type(4) { animation-delay: 9s }
#F-dynamicbg-box > div:nth-of-type(5) { animation-delay: 12s }
#F-dynamicbg-box > div:nth-of-type(6) { animation-delay: 4s }
#F-dynamicbg-box > div:nth-of-type(7) { animation-delay: 15s }
#F-dynamicbg-box > div:nth-of-type(8) { animation-delay: 18s }
#F-dynamicbg-box > div:nth-of-type(9) { animation-delay: 20s }
#F-dynamicbg-box > div:nth-of-type(10) { animation-delay: 16s }
@keyframes dynamicDiv {
form { top: 105vh; transform: scale(1.2); }
to { top: -13vh; transform: scale(1) rotate(60deg); }
}
</style></head>
<body>
<div id="F-dynamicbg-box">
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
</div>
</body>
<script>
var box = document.getElementById(‘F-dynamicbg-box‘),
div = box.getElementsByTagName(‘div‘),
math = [0,1];for (var i=0;i<div.length;i++) {
math[1] = F_getSJS(100,40,9)
if(math[1] != math[2]){
div[i].style.width = math[1] + ‘px‘;
div[i].style.height = math[1] + ‘px‘;
math[2] = math[1];
}
}
for(var i=0;i<div.length;i++){
div[i].style.left = F_getSJS(85,15,8) + ‘vw‘;
div[i].style.transform = ‘rotate(‘ + F_getSJS(360,5,9) + ‘deg)‘;
}
</script </html>
原文：http://www.cnblogs.com/li-123/p/7008858.html