Often I am not too sure which way I should go, Q&A or discussion. I wonder if the administrator could move it to Q&A for me or whether I should start another one as Q&A.

Can I say, by default all Internet browsers get the pages including embedded video and embedded music from the local cache (local computer) first then the ISP cache. I have supposed all Internet browsers have some mechanisms to compare what are in the caches before they go to the web servers in order to minimize traffic.

When we hit "F5", do they reload from the ISP cache or the web server where the pages reside?