title: Is Content-Type HTTP header always required?
body: <p>This question is about browser behavior as well as protocol specification for linking, importing, including or ajaxing css, js, image and other resources from within html, js or css files.</p>
  
  <p>While testing static files and compressed content delivery in different browsers, I found that some browsers start behaving differently if you move away from conventions. For example, IE6 creates problem if you do not send <code>Content-Disposition: inline;</code> header for all inline css and js etc files, and a recent version of safari does not properly handle pre-compressed gzip CSS files if you use file extension <code>.gz</code> like in <code>main-styles.css.gz</code>.</p>
  
  <p>My question is about the behavior of browsers about <code>Content-Type</code> response header. Since <code>&lt;link&gt;</code>, <code>&lt;script&gt;</code> and <code>&lt;img&gt;</code> tags already reasonably specify the content type of the resource, can this header be safely skipped, or do some browsers require it for some historical reason?</p>