title: Cache CSS and JS files
body: <p>When I refresh my website in less than 2-3 minutes, Firebug shows these nice requests:</p>
  
  <pre><code>1. /core.css          304 Not modified
  2. /core.js           304 Not modified
  3. /background.jpg    304 Not modified
  </code></pre>
  
  <p>BUT when I refresh after >3 minutes, I get:</p>
  
  <pre><code>1. /core.css          200 OK
  2. /core.js           200 OK
  3. /background.jpg    304 Not modified
  </code></pre>
  
  <p><strong>Why my CSS and JS files are downloaded again and images aren't?</strong></p>
  
  <p>I'm using ASP.NET MVC 3, I DON'T use <code>[OutputCache]</code>, and in my <code>/Content</code> folder (where all css, js and img files live in subfolders) I have this Web.config:</p>
  
  <pre><code>&lt;configuration&gt;
      &lt;system.webServer&gt;
          &lt;staticContent&gt;
              &lt;clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="1.00:00:00" /&gt;
          &lt;/staticContent&gt;
      &lt;/system.webServer&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>which sets HTTP header <code>Cache-Control: max-age=86400</code> ONLY. So basically CSS, JS and images are treated the same way, but somehow CSS and JS don't get cached for a longer period... why is that?</p>