Just to add another debugging option for you to the excellent answer that tachyon provided above. To see if it is the browser that is caching the file, you can try a full refresh of the page by clicking the refresh button while holding down the ctrl or shift key (depending on the browser you are using). This should refresh every element on the page regardless of what is in the local cache.

Of course, you could still hit a caching proxy server along the way, and it's possible that some browsers don't support the full refresh, but it might give some help.