title: Displaying content of 302 Redirect - or HTTP-compliant waiting screen
body: <p>I'd like to have a waiting screen in HTML drawn before user enters the site because of some long-running auth processes that are out of my control. I'd like that screen to be fully HTTP-compliant, i.e.:</p>
  
  <ul>
  <li>it should not respond with <code>200 OK</code> if there's no actual content yet available (which eliminates an option to display an empty page placeholder with loading indicator and load the content using AJAX call in the background)</li>
  <li>it should respond with <code>302 Redirect</code> if there is actually any redirection (that eliminates HTML's Meta Refresh feature).</li>
  </ul>
  
  <p>The only "third way" I can see is to rely on standard 302 redirections. But I'll need the actual content of the request that resulted in 302 response to be rendered to the user for the time of waiting for the second request (with "please wait" info or something). In most (all?) cases, browsers do not draw the content of those requests, just go and wait for the data from redirection.</p>
  
  <p>The questions are:</p>
  
  <ol>
  <li>in what cases the content of 302 Redirect request is rendered? is it possible to force browsers to render it before redirecting?</li>
  <li>is there another way to approach the problem without breaking the HTTP protocol? or is <code>200 OK</code> status for the page without any content initially not breaking the protocol?</li>
  </ol>