Precaching your .swf script?

I am trying to figure out how to code your .swf so that when they are displayed in a browser, the browser automatically caches the .swf so that it’s the most up to date file. Alot of times when I am updating a site they won’t display properly in someone’s browser until they empty the cache or delete temporary internet files because they old .swf files are still displayed from the browser’s cache. I have heard that there is a way to add a script to your .swf files so that the html files that they are embedded in will always call on the most recent file. Does anyone know how to do this?

My other question is would I need to use the script on all my .swf’s that are loaded externally or just the main .swf that is embedded in the html file which contains the movie clip loader?