substack/node-browserify — comment on commit 2d6b2120a34cb0331f3bd51e9cc41f68efda2879
File:  line 0
By pacovell:

Right now I'm sending both the expires and the etag header, and the browser (Chrome and Safari, at least) will issue a GET with the following headers:

If-Modified-Since:Tue, 15 Nov 2011 23:28:29 GMT
If-None-Match:"5c6f2f5294db54eecf2f29bff5db8a82"

So it may be best to just send the expires header, which will prevent query altogether, and combine that with the unique filename. I don't see any downside, am I missing anything?