I just switched from Chrome to Firefox Developer Edition for web development and discovered that by default I can’t navigate through links with the tab key.
A stack overflow question pointed to the problem. The responder says that Mozilla is being true to OS settings on Mac (what I’m using), hence keyboard navigation doesn’t work for links out of the box. I suppose Chrome is not respecting these settings for whatever reason. Safari behaves similarly to Firefox in this case, as should be expected based on the logic behind the decision.
This can be fixed in Firefox by creating a new integer preference called “accessibility.tabfocus” and setting it to 7.
At least for the developer edition of Firefox I think something like this should be enabled by default, since most developers will want to design for accessibility.