I'm trying to improve the caching policy for a web site.
I'm implementing an aggressive caching strategy first, for resources that won't change at all, and would like files like jquery-min for example to be downloaded only once, and then be served from browser cache.
I used Apache Mod-Expire module to accomplish this, and it's working pretty well.
However, I'm surprised that when I completely remove my cache-control configuration, Firefox browser does not re-download jquery file : it already gets it from the cache, without any instruction from me. How is Firefox making this kind of decision ? Is it related to the ETag hash ?
Here are the headers I get without my configuration for that particular file :
Accept-Ranges bytes
Connection Keep-Alive
Content-Encoding gzip
Content-Length 27073
Content-Type application/javascript
Date Fri, 23 Aug 2013 09:48:06 GMT
Etag "225f8-13309-4e385823c7b80"
Keep-Alive timeout=15, max=99
Last-Modified Fri, 09 Aug 2013 15:34:22 GMT
Server Apache
Vary Accept-Encoding
Can anyone explain to me what is the browser behavior when there's no Cache-Control policy defined ? is it browser dependant ?
Thank you,
Mathieu.