IIS and Static content?

Question

According to Ultra-Fast ASP.NET: Chapter 3 - Caching:

Files that the browser retrieves from the server should be stored in the browser’s cache as lo

Answer 1

1. The static content is the one that IIS is read and send to the browser with out any processing. There you can setup IIS to include some Cache-Control Header to cache it on clients browser computers.
2. You can do that ether by direct setup IIS, ether by commands on web.config as you say. The commands that you add on web.config and concern the IIS, did not have to do with asp.net it self, but the IIS, and IIS saves his configuration on a different file, so when you change that cache control headers direct on IIS you do not see them on web.config.
3. Now for the static content like images, CSS, JavaScript, and other similar files they say that you can follow the "never expire" policy by adding 10 years expire.
4. The issue here is that if you can not change the content of the static file, if for example you cache a javascript file with 10 years, and you make a small change on it, then you need ether to change the file name, ether to add some parameter at the end of it.
5. Now the <%@ OutputCache on a control is referred to the server cache and not to the client, and what is actually do is to cache the render of the control on the server so the next time you ask it to not lose time to renders it again but read it from cache - is still send it to the browser.

And you can also read this answer for some more: What are difference between IIS (Dynamic and Static) cache,OutPutCache and browser cache