Why use a form tag when you're submitting via ajax?

Question

Philosophical question:

Say I\'ve got a web app that requires javascript and a modern browser, so progressive enhancement is not an issue. If my form is be

Answer 1

AJAX is great but as JamWaffles (+1 to him) said, using form tags provides a fallback method.

Personally I use form tags, even for things I submit with AJAX because it is syntactically clear and makes it easy to grab all inputs within a specific form. Yes you could do this with a div or whatever too but as I said, using a form is syntactically nice.

Incidentally, screen readers treat the content inside a form differently so there are accessibility issues to be considered whichever way you choose to go. Note that anecdotal evidence suggests that Google considers accessibility in its rankings so if SEO is a concern for you, use a form and do it right.