How do you test your web UI to see if it renders uniformly across different browsers?
browser, testing, user-interface
Solution
May I recommend browsershots where you can submit pages and have them rendered out in a variety of browsers with various things set on or off such as Flash and JavaScript. At the end of the day you will still want to install FF, IE6-8, Opera and Safari/Chrome for testing manually. Also, if you've got a friend with a Mac (or a PC if you're using a Mac) get them to test in Safari too as I've personally found differences in the way both of them render the same page.
I'd also recommend that you develop mainly in Firefox and regularly check it in IE6 as you work. IE6 is the one that will mostly screw up so if it's working in both it's more likely to be working in all.
When you find rendering weirdness try and fix it in your markup and CSS first before resorting to CSS hacks as they can lead to 'interesting' problems later or in other browsers.
Problem
Tools like Selenium are good for testing user interactions on the web UI. However, I was curious what are people approaches for strictly testing and verifying that web pages are rendered correctly across a set of browsers? Is this even possible?