We have a WordPress website which loads sufficiently in every browser I've tried, except for IE. For some reason in IE, it seems to freeze the browser for a few seconds every single time the page is loaded, doubly so if it has to load a page with an iframe of another page. The user has to wait awhile before they can interact with anything on the page.
Someone suggested we could use WP Supercache to solve the issue, but I've had problems with this plugin in the past and am reluctant to rely on it, especially since this seems to be only a problem in IE.
What is the best way I can troubleshoot this issue? How do I find out which scripts in the header, or footer, etc. is causing it? Is there a quick way to do so, or do I just need to start eliminating variables within the theme?
Thanks to this thread I just found, the answer appears to be fancybox: Fancybox causing slow load times in IE?
Specifically, the IE-specific filters in the CSS file for fancybox. I removed those filter styles, and it loads fine now.