title: HTML5 Make webrequest from cached iframe
body: <p>We have a main page which contains a frameset. This has 2 frames (frame a and frame b). Using the Application cache (HTML5) we cache the main page and frame a. Frame b is a page which is retrieved like any web page.</p>
  <p>Now we found out that, when a page is cached, it is not able to do web requests. Therefore frame a can not collect data using a web request, frame b can. (Just a normal $.get or $.post using jQuery).</p>
  <p>With Frameset becoming obsolete with the HTML5 specification, we are looking for a different way to set this up. So we come down to the iframe tag. The situation would still be the same, although it is set in iframes.</p>
  <p>Now we run into the problem that, whenever a single page that is loaded in the iframes, no iframe can make a web request.</p>
  <p>The setup:</p>
  <p>Main page:</p>
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html manifest=&quot;CacheManifest3.ashx&quot;&gt;
  &lt;head&gt;
      &lt;title&gt;Testpage for frames&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;iframe height=&quot;200px&quot; width=&quot;200px&quot; style=&quot;position: relative; background: blue;&quot; src=&quot;frame_c.html&quot; &gt;&lt;/iframe&gt;
      &lt;iframe height=&quot;200px&quot; width=&quot;200px&quot; style=&quot;position: relative; background: Yellow;&quot; src=&quot;frame_d.html&quot; &gt;&lt;/iframe&gt;
  &lt;/body&gt;
  
  &lt;/html&gt;
  </code></pre>
  <p>Frame a and b (the only difference is the a and the b):</p>
  <pre><code>&lt;script src=&quot;Scripts/jquery-1.7.1.js&quot; type=&quot;text/javascript&quot;&gt;&lt;/script&gt;
  &lt;p&gt;Frame a&lt;/p&gt;
  
  &lt;script&gt;
      function doclick()
      {
          $.post( &quot;WebServices/SiteWebService.asmx/Test&quot;, null, function ( data )
          {
              alert( 'Done! ' + data );
          } );
      }
  &lt;/script&gt;
  
  &lt;button onclick=&quot;doclick();&quot;&gt;Click for webrequest&lt;/button&gt;
  &lt;button onclick=&quot;alert( 'Alert!' );&quot;&gt;Click for alert&lt;/button&gt;
  </code></pre>
  <p>Cache Manifest:</p>
  <pre><code>CACHE MANIFEST
  #v1
  CACHE:
  Frametest2.html
  frame_a.html
  </code></pre>
  <p>Now, to come down to the question: Is it possible to keep at least 1 iframe loaded from the internet while the others are cached, so, that it is still possible to make webrequests from that single iframe?</p>
  <p>We want this to make sure out application gives as real time as possible information back to the parent company, while the application is being run from a smartphone and/or tablet which might be brought into awkward places. (Cellars, under houses, big bridges or any other place which may interfere with the signal) When the signal is lost and later restored, we want to send the information back, without a user action. With a scenario like this, we think we can get it to work.</p>
  <p>Edit: Updated to remove testing parameters of the Sandbox attribute.</p>