I have the RunTime.CachePath set, and the browser is indeed saving files into the folder, but it's never actually using them. Every time it visits another page, it creates an identical entry in the cache path but with a different name. How can I get the caching to actually work?

An important note is that I have the browser pointed to a local web server I wrote entirely custom (for a variety of reasons). I've tried setting an Etag in the response header and the browser is correctly sending the If-None-Match header with the corresponding Etag but that doesn't help the cache problem. Do I need to form the header differently?

Another important note is that all of the links it's having problems with are relative, and not absolute... BUT the files those pages are using ARE the same exact file in the same exact place, they're just referenced differently in each page because each page is in it's own folder, so the relative path to them is different. Would using absolute paths help?

I managed to figure it out. The problem was the response header. I needed to send a different HTTP code (304 Not Modified) for the browser to actually use the cache along with checking the Etag and the last modified date. It works now.