Currently Facebook does not allow developers to use iframes on Fan Page Tabs:
"The one exception: if you absolutely must create an application that appears as a tab on a Facebook Page, you will need to use FBML for now; tabs do not currently support iframes directly. We will be transitioning tabs to iframes later this year -- please see the developer roadmap for more details." http://developers.facebook.com/docs/reference/fbml/
But according to the developer roadmap they will soon (Q4 2010):
"We are also moving toward IFrames instead of FBML for both canvas applications and Page tabs. As a part of this process, we will be standardizing on a small set of core FBML tags that will work with both applications on Facebook and external Web pages via our JavaScript SDK, effectively eliminating the technical difference between developing an application on and off Facebook.com. We will begin supporting IFrames for Page tabs in the next few months. Developers building canvas applications should start using IFrames immediately. By the end of this year, we will no longer allow new FBML applications to be created, so all new canvas applications and Page tabs will have to be based on IFrames and our JavaScript SDK. We will, however, continue to support existing implementations of the older authentication mechanism as well as FBML on Page tabs and applications." http://developers.facebook.com/roadmap
Anyone know the status of this of have a better idea of what methods Facebook developers are using for Iframe apps on Fan Pages Tabs?
According to their logic, I should develop the canvas application as an Iframe now, but how is it supported on the Profile Tab?