Aggressive JavaScript caching

Question

I\'ve run into a problem where I make changes to a few JavaScript files that are referenced in an HTML file, but the browser doesn\'t see the changes. It holds onto the copy

Answer 1

With every release, we simply prepend a monotonically increasing integer to the root path of all our static assets, which forces the client to reload (we've seen the query string method break in IE6 before). For example:

• Release 1: http://www.foo.com/1/js/foo.js
• Release 2: http://www.foo.com/2/js/foo.js

It requires rejiggering links with each release, but we've built functionality to automatically change the links into our deployment tools.

Once you do this, you can use Expires/Cache-Control headers that let the client cache JS resources "forever", since the path changes with each release, which i think is what @JasonCohen was getting at.