Developing for multiple versions of Firefox

Lately, we have noticed that not all Firefox versions are playing the same game when it comes to layout and I wanted to find out if there is a definitive guideline when it comes to developing for Firefox.

What we're having to do is use Portable Versions of FF and then test across these versions but this is becoming a major head开发者_JAVA百科ache! If someone knows of a script that will fix these issues across different versions of Firefox, I would appreciate it. Else, if there is some guidelines I can follow, I would appreciate that too!

Thanks, James

The behavior you see might be an intentional change (e.g. to comply with the HTML5 spec) or a bug (a regression). If it is the former it should be listed on https://developer.mozilla.org/en/Firefox_4_for_developers or https://developer.mozilla.org/en/Firefox_5_for_developers. These pages are usually created in advance of a major release (e.g. https://developer.mozilla.org/en/Firefox_6_for_developers exists already) so that you can see if something affecting you is coming up. If a change breaks backwards compatibility there should be hints on how web developers can deal with it.

If it is a bug then it should be reported on https://bugzilla.mozilla.org/ along with a minimized testcase, marked with the "regression" keyword. Regressions that are reproducible and that affect web applications usually get looked at pretty quickly.

That's a very broad answer to a very broad question. For more useful answers you should really provide some details with your question.