title: Mobile device resolution (width, height) screen size header
body: <p>It seems there is no real standard for specifying &quot;screen-size&quot; in a http header from a user agent.</p>
  <p>For example, the two headers below:</p>
  <pre><code>X-UP-devcap-screenpixels: 320x240
  </code></pre>
  <p>or</p>
  <pre><code>UA-pixels: 320x240
  </code></pre>
  <p>are two commonly used headers.
  The second is used by Windows Mobile devices mostly.
  The <strong>X-UP</strong> looks like it comes from the UP browser gateway.</p>
  <p>Another option is</p>
  <pre><code>X-Screen-Width: 320
  X-Screen-Height: 240
  </code></pre>
  <p>the X-Screen-Width might be made a up header.</p>
  <p><em>My question is:</em></p>
  <p>What is a good standard to adopt on our &quot;transcoder&quot; going forward?  It's not really a full web browser, but is mostly for limited sites.  But it should be the standard that would be adopted by Opera Mini/GWT etc.</p>
  <p>Neither Opera Mini nor Google Web Transcoder sends this information through in their HTTP requests.  I guess they expect the site to look up the phone model, and thereby the screen width and height, on the server side.</p>
  <p>I actually found this <a href="https://www.rfc-editor.org/rfc/rfc4229" rel="nofollow noreferrer">RFC 4229</a> called HTTP Header Field Registrations. It's kind  of outdated, and a mission to contribute fixes to.</p>
  <p>If I had to see what's used mostly in the field, I would probably end up going with &quot;UA-Pixels&quot;.</p>
  <p>Some more references</p>
  <ul>
  <li>Some devices (mostly Windows Mobile again) have a 320x240 value in the user-agent header</li>
  </ul>