title: PHP handling multipart/form-data
body: <p>Sorry for the title, because I don't know how to name this problem. Please consider the following code</p>
  
  <pre><code>&lt;?php
  var_dump($_POST);
  ?&gt;
  &lt;form name="submit_form" id="submit_form" method="POST" enctype="multipart/form-data"&gt;
      &lt;input type="hidden" name="update" value="y"&gt;
      &lt;input type="file" name="supplement_file" id="supplement_file" class="btn_general" /&gt;
      &lt;input type="submit" /&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>It's a PHP that simply do printing the submitting information. The first run, it displays empty, that makes sense. However, after I click submit, it still shows empty. But the request payload has been set already. I can see it via network tab in console.</p>
  
  <pre><code>------WebKitFormBoundaryO78Y428dBFHmIDbk
  Content-Disposition: form-data; name="update"
  
  y
  ------WebKitFormBoundaryO78Y428dBFHmIDbk
  Content-Disposition: form-data; name="supplement_file"; filename="supplement2.wmv"
  Content-Type: video/x-ms-wmv
  
  
  ------WebKitFormBoundaryO78Y428dBFHmIDbk--
  </code></pre>
  
  <p>What I expect is I can see the <code>"update"="y"</code> after I submit this form.</p>
  
  <p>I am using PHP 5.3 is that is the problem? And the content-type is strange. It's <code>Content-Type:text/html</code> in this submit. Am I missing something?</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>The header information of the request</p>
  
  <pre><code>Connection:Keep-Alive
  Content-Length:369
  Content-Type:text/html
  Date:Tue, 30 Dec 2014 10:01:22 GMT
  Keep-Alive:timeout=5, max=100
  Server:Apache/2.2.17 (Win32) mod_ssl/2.2.17 OpenSSL/0.9.8o PHP/5.3.4 mod_perl/2.0.4 Perl/v5.10.1
  X-Powered-By:PHP/5.3.5
  </code></pre>