Firefox seems to maintain an internal, invisible "focus position". Click on the red text, then hit Tab and note how "delta" is being focused. Chrome will focus "alpha", because that's the first element of the document's navigation sequence from the position of <body>. Internet Explorer shows the same behavior, but only if you hit Tab within one second (best guess) of clicking anywhere.

Note: There is nothing special about the red text, it's just meant as a target for you to click on. Really you can click anywhere. For example to the right of one of the input elements, and focus will shift to the next one.





click on this text, then hit Tab