Revision 1106797 of 412 Precondition Failed

<div>{{HTTPSidebar}}</div>

<p>The HTTP <code><strong>412</strong></code><strong><code> Precondition Failed</code></strong> client error response code indicates that access to the target resource has been denied. This happens with conditional requests on methods other than {{HTTPMethod("GET")}} or {{HTTPMethod("HEAD")}} when the condition defined by the {{HTTPHeader("If-Unmodified-Since")}} or {{HTTPHeader("If-None-Match")}} headers is not fulfilled. In that case, the request, usually an upload or a modification of a resource, cannot be made and this error response is sent back.</p>

<h2 id="Status">Status</h2>

<pre class="syntaxbox">
412 Precondition Failed</pre>

<h2 id="Specifications">Specifications</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Title</th>
  </tr>
  <tr>
   <td>{{RFC("7232", "412 Precondition Failed" , "4.2")}}</td>
   <td>Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<p class="hidden">The compatibility table in this page is generated from structured data. If you’d like to contribute to the data, please check out <a href="https://github.com/mdn/browser-compat-data/README.md">https://github.com/mdn/browser-compat-data/README.md</a> and send us a pull request.</p>

<p>{{Compat}}</p>

<h2 id="See_also">See also</h2>

<ul>
 <li>{{HTTPStatus("304")}}</li>
 <li>{{HTTPHeader("If-Unmodified-Since")}}</li>
 <li>{{HTTPHeader("If-None-Match")}}</li>
</ul>