Wow ... that's interesting as all my tests with Webforms outside of the IE web browser failed - including Safari and mobile browsers! I'm confused as Webforms only supported IE and only up to version 9 as well.
I have been able to run PB Web applications across most browsers when they were built using EAServer and PB's Web Target that produced JSP code.
Have you been modifying the Webform HTML, C# and jScript code in order to accomplish this?