title: How to access ETag header with jQuery AJAX request?
body: <p>I'm using a jQuery ajax call to request data from a server that is sending an ETag in the HTTP response headers. I need access to the header, but when the request succeeds and I call jqXHR.getAllResponseHeaders(), I only see a subset of the headers returned by the server. </p>
  
  <p>Example: </p>
  
  <pre><code>var jqXHR = $.ajax({
          type: 'GET',
          url: &lt;my api url&gt;,
          dataType: 'json',
          ifModified: true,
          success: function (result) {
            var headers = jqXHR.getAllResponseHeaders();
            console.log(JSON.stringify(headers));
          });
  </code></pre>
  
  <p>The headers I see from the jqxhr are:</p>
  
  <pre><code>Pragma: no-cache\r\n
  Last-Modified: Wed, 22 Jan 2014 10:45:14 +0000\r\n
  Content-Type: text/html\r\n
  Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0, no-cache=\"set-cookie\"\r\n
  Expires: Sat, 26 Jul 1997 05:00:00 GMT\r\n
  </code></pre>
  
  <p>The actual headers returned from the server (observed in chrome dev tools):</p>
  
  <pre><code>Access-Control-Allow-Origin:*
  Cache-Control:no-cache="set-cookie"
  Cache-Control:post-check=0, pre-check=0
  Cache-Control:no-store, no-cache, must-revalidate
  Connection:keep-alive
  Content-Encoding:gzip
  Content-Length:407
  Content-Type:text/html
  Date:Fri, 24 Jan 2014 20:27:54 GMT
  ETag:"29d8d1d98115057fe902b520199ea1b3"
  Expires:Sat, 26 Jul 1997 05:00:00 GMT
  Last-Modified:Thu, 23 Jan 2014 07:14:57 +0000
  Pragma:no-cache
  Server:nginx/1.1.19
  Set-Cookie:AWSELB=F3E9557318EB956CA386FC6CB4270164AD7830493699A2B6AED008F4C5F9DB5952A2A1072C33DDC32DEDE0CA6A3734EBAFD51B57A7A093B69A36A6659EF493E1B92BA63DE6;PATH=/
  X-Powered-By:PHP/5.4.19
  </code></pre>
  
  <p>I need to access the ETag header, but it seems as if jQuery or chrome are hiding it from me. I have tried the same code in Firefox with the same results. Can someone help me with this?</p>