We're using a custom domain for our zoho forms which was set up using this tutorial.  We are embedding our forms with javascript/iframe and it all works just fine.  Only problem is that after the form loads, it refreshes a few seconds later and the browser interprets this as a new page view.  This makes for a poor user experience because clicking back means that nothing happens until clicking back a second time.  The other problem is that people might begin filling the form and then it refreshes, forcing them to start over.  This refresh only happens once, and soon after the initial load.