For some strange reason, Firefox caches ASP.NET pages even if you tell it not to. This could create problems with the back-button. Normally you can tell the browser how to cache your web page in two ways. You can use meta tags or set some HTTP headers. To be absolutely sure that all browsers understand you cache policy, you could combine the two. However, when you don’t want the browser to cache your page, Firefox caches it anyway. It does so because it cannot se any difference between how the page looked before and after you pressed the back-button. This issue drove me absolutely nuts today, and it took me a while to come up with a solution.