Is there a standard for what actions F5 and Ctrl+F5 trigger in web browsers?
I once did experiment in IE6 and Firefox 2.x. The F5 refresh would trigger a HTTP request sent to the server with an If-Modified-Since header, while Ctrl+F5 would not have such a header. In my understanding, F5 will try to utilize cached content as much as possible, while Ctrl+F5 is intended to abandon all cached content and just retrieve all content from the servers again.
But today, I noticed that in some of the latest browsers (Chrome, IE8) it doesn’t work in this way anymore. Both F5 and Ctrl+F5 send the If-Modified-Since header.
So how is this supposed to work, or (if there is no standard) how do the major browsers differ in how they implement these refresh features?
