So this may be a very specific issue but it could help someone struggling with it.
Working on a mobile project utilizing JQM and
Flexslider by Muffin (this particular jQuery slider is mobile optimized hence the reason we're using it).
In order for all the slides to load before the flex slider starts running we needed to put the call to the flex slider inside of $(window).load() instead of $(document).ready().
This worked perfectly in every browser except IE9 which would literally crash. It would try to recover and then crash again.
The front page, where it was crashing, had two separate sliders - one at the top of the document and the other in the footer. Flexslider has a variety of animations and it is built to run multiple sliders on a single page.
I narrowed it down to the animation itself. When you have 1). Two sliders on one page, and 2. They both have the same "slide" animation, and 3. They're called inside of $(window).load() you will crash IE9 every time. However, Flexslider hasn't had this problem on any other dev project - only where JQM is involved.
(Extra info: we're using version 1.0.1 of JQM and ajax is disabled)
This is because for some reason JQM doesn't like it when you try to run Flexslider after JQM is initiated (either through window.load or positioning the script after JQM). Like I said Flexslider normally never has this problem, only when JQM is used.
I have no idea why this is, and normally I'd say this is a Flexslider issue but since it only happens when JQM is used, it is a factor to consider. If anything this is another IE stumble....
My solution -
Simple: Change one of the animations to "fade"
Less Simple: Use IE conditional statements to change one of the animations to fade for IE users.