在我们的3G版网站的项目中使用了html5 application cache，将大部分图片资源、js、css等静态资源放在manifest文件中。
没想到上线第一天就遇到了严重问题：application cache会默认缓存当前页面！！！就算我们有如下设置：
NETWORK:*
也就是说，对于所有的动态页面，application cache会缓存起来，用户怎么刷新都是老的！
而且手机浏览器还很难清除掉，也不支持js清除！
花了一个上午，尝试了很多办法，查了很多资料，都没能清除掉客户端的缓存。一上午被用户投诉惨了。
最后还是万能的stackoverflow救了我：
Do not use appcache unless it is REALLY 100% EXACTLY WHAT YOU WANT TO DO
Even if it IS 100% EXACTLY WHAT YOU WANT TO DO, *DO NOT* use appcache until you are 100% CERTAIN that you are not going to make a single change to that page (or any file that it links to) for a LONG time.
Delete the manifest file from the server -- if the browser can't find the manifest file, then it will clear its cache... ...this will also turn caching off for everyone.
Don't turn it on again until it's 100% CORRECT
Dealing with appcache is miserable, often.
解决办法很简单，在服务器端删除掉manifest文件，并且慎用application cache
当然，也有办法是用application cache，同时能绕过自动缓存当前页面的问题。那就是用iframe
