title: Difference between Pragma and Cache-Control headers?
body: <p>I read about <em>Pragma</em> header on <a href="http://en.wikipedia.org/wiki/List_of_HTTP_header_fields" rel="noreferrer">Wikipedia</a> which says:</p>
  
  <blockquote>
    <p>"The Pragma: no-cache header field is an HTTP/1.0 header intended for
    use in requests. It is a means for the browser to tell the server and
    any intermediate caches that it wants a fresh version of the resource,
    not for the server to tell the browser not to cache the resource. Some
    user agents do pay attention to this header in responses, but the
    HTTP/1.1 RFC specifically warns against relying on this behavior."</p>
  </blockquote>
  
  <p>But I haven't understood what it does? What is the difference between the <code>Cache-Control</code> header whose value is <code>no-cache</code> and <code>Pragma</code> whose value is also <code>no-cache</code>?</p>