重写 Response.Filter 就可以获取或更新输出到浏览器的内容

资料:

https://weblog.west-wind.com/posts/2009/Nov/13/Capturing-and-Transforming-ASPNET-Output-with-ResponseFilter

http://stackoverflow.com/questions/14925433/asp-net-response-filter

http://www.cnblogs.com/cnshangsha/archive/2010/05/06/Ten_practices_aspnet_performance.html