I have a web application written in pure JavaScript (no pre-generated HTML except for the document which loads all the JS files).

This app contains a login form which is created dynamically when the document.ready event event is triggered. I trick the browser into displaying the "Remember password?" dialog by posting the login form into a hidden iframe before logging in using ajax (in Firefox the password appears on the saved password list, so this part obviously works) but saved passwords never get filled in after the login screen is loaded again at a later time. The same thing happens in Firefox and Safari.

Is there something I can do or some function I can call to trigger autofill?

UPDATE: autofill works in Safari on initial page load, but not when user logs out and the login form is recreated without a page reload. In Firefox it never works.