Let ASP.NET know you have a powerful web browser like Firefox or Opera

By default ASP.NET 1.x downgrades its reponses to lower-level HTML with web browsers other than Internet Explorer 5+.
The result is that browsers like Mozilla, Firefox, Opera or Safari get a different HTML than IE 6, while they could handle it. As a developer this is a nightmare because when you develop a page with IE, and then test it with Firefox, it looks all broken and you start cursing the Mozilla team and the consortiums in charge of the standards. You end up having to do the work twice, once for IE, once for the other browsers.

But wait! The solution is simple and you can quickly get rid of all those problems!
ASP.NET relies on so called "browser caps" to know what HTML to render. The good news is that you can change these browser caps simply using your web.config file.

Rob Eberhardt did a great work and provides us with ready-to-use browser caps that you can integrate into your configuration files.