Support for newer version of browser

Question

How would you analyze your web application to asses the amount and kind of changes you will have to do to be able to support a new browser or a newer version of the same browser.

I have IE7 in mind, but am looking for general advice.

Added clarification:

I already have an existing application. Not designing a new application, We need to make it work with new browsers

So I need to estimate how difficult it will be or how much work it will be

Answer 1

check that you do not exploit any of the bugs in IE6. when IE6 doesn't violate the standard, it rather adheres to it.

unfortunatly ie6 is a closed source application so you will never know how it works.

lists of bugs:

• http://www.gtalbot.org/BrowserBugsSection/MSIE6Bugs/ (very extensive)
• positioniseverything.net/explorer.html

Answer 2

In case of Internet Explorer, this might help: ie7-js.

It's a javascript library written to make IE5-8 behave like a standards-compliant browser.

Answer 3

Generally browsers become more W3C compatible with future. So good is to have two CSS files. one to make it W3C complaint and other for hacky ones. When newer versions comes you mainly need to delete from your hacky CSS.New browser also might support new features like HTML 5.. but they should not break the existing rules.