I'd like to leverage a (to me) complicated Javascript, Photoswipe. The author is clear that they don't support IE 7, and although the demo site does function to some degree in IE 7, the instance my team built does not.
Rather than try to modify the script, I'd like to use something like Yep/Nope to detect which Javascript feature is failing and provide a simpler alternate gallery that I know works well in old browsers. I'm trying to avoid user-agent sniffing.
Is there a tool or method available to sort out what to feature-detect against in a script that you don't know the ins-outs of personally?