I always thought that the javascript files were cached by the browser, so I was suprised to see a lot of identical .js files in my browser's cache. They appear to be cached by Session/Espace, therefor the files are not cached as they should be?

Does anybody have an insight on this?

Thanks in advance,
Rodrigo Catarino

Looking at your attached image, I'd say this is related to having cookies turned off.

You probably have unchecked the "Use Cookies" check box option in eSpace's advanced tab (in eSpace properties).
In this mode, the session id is stored in the URL instead of in cookies. As the browser caches files based on URLs, it will not cache the file along different sessions.
If you turn the check on (default o0ption, at least in version 4.0), Î think the behavior you described will not happen.