title: Browser caching javascript and css files
body: <p>I understand that the browser is forced to fetch a new version of the cached JS file when the file name is changed or a query string is added to it.</p>
  
  <p>We don't do this and until now we've never had issues with browser serving stale files. Recently, we are seeing some users using IE9 who complain about the browser serving cached JS/CSS files. This issue is not consistent across everyone using the site. </p>
  
  <p>My understanding is that when the file name or query string is not changed, but the JS file content is changed, the browser would fetch the new version.</p>
  
  <p>Why is this happening and why is it not consistent?</p>
  
  <p>Any thoughts?</p>