 <p>How about adding a '?2' to the tag?</p> <p><code>&lt;script src="a.js?2"&gt;&lt;/script&gt;</code></p> <p>The server should return the same file with or without the '?2', but the browser should see it as a different file and redownload. You can just change this query string whenever the file is changed.</p> <p>adapted from: <a href="http://blog.httpwatch.com/2007/12/10/two-simple-rules-for-http-caching/">http://blog.httpwatch.com/2007/12/10/two-simple-rules-for-http-caching/</a></p>