I am in the process of beta testing a catalog widget that my company built, that can be deployed either as a standalone page or within an iframe. It works fine when called directly, or in an iframe in a page called by most browsers (tested in various versions of Firefox, Chrome, IE11, IE10 and IE9). However, in IE9, it runs excruciatingly slowly. Javascript functions bound to buttons do not respond unless the page is allowed to sit for a very long time. As the user base for my client includes a large number of users stuck with IE9 by institutional policy, this is a serious problem for my client.
Here's an example of the direct link to the widget: http://bankers.confedge.com/ap/widget/events.cfm?widgetKey=29lQuI25oLhxi0vOZwq8&grp=MT
Here it is in an iframe: http://www.texasbankers.com/web/Texas_Bankers/Webinar_Catalog.aspx
It does take a while longer to load in the iframe than I'd like, regardless of browser (it is a very data-intensive application), but in all other browsers it is fully responsive once loaded. Only in IE9 and earlier does it hang up. I do notice a great degree of variability in the load times at different times of day, suggesting that my client's server load may be exacerbating this problem.
Let me know if there's any code I can provide that might help identify the problem, or if there's anything that can be done to optimize this for IE9.