<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title></title> <script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script> <style> div{ width: 100%; height: 200px; background-image: ; background-size: 100% 100%; } </style> </head> <body> <div id="preView" width="100%" height="500px"> </div> <script type="text/javascript"> var bodyBgs = []; //创建一个数组变量来存储背景图片的路径 bodyBgs[0] = "img/b_img.jpg"; bodyBgs[1] = "img/b_ing2.jpg"; //Math.round四舍五入取整；Math.random()取随机数； //下边是取0-1之间的随机数 var randomBgIndex = Math.round(Math.random()*1); var imgsr=bodyBgs[randomBgIndex]; $("#preView").css({"background-image":"url("+imgsr+")"}); </script> </body> </html>
原文：http://www.cnblogs.com/flyings/p/5577236.html