I ran into this too a few months while back, oddly enough with IE. Some proxy server or something was caching old versions of CSS files. After messing around

I ran into this too a few months while back, oddly enough with IE. Some proxy server or something was caching old versions of CSS files. After messing around forever with HTTP headers, I found the easiest way to deal with this is the href="blah.css?i=12345" solution mentioned in the article. Works for JS files too. Rails makes this very easy with asset timestamps: http://api.rubyonrails.org/classes/ActionView/Helpers/AssetTagHelper.html http://api.rubyonrails.org/classes/ActionView/Helpers/AssetT... (well, "easy" sort of... until you have multiple web servers and the times get slightly out of sync)