title: Sandbox iframe attribute isn't preventing redirects in FIrefox
body: <p>I'm trying to get iFrame sandboxing to work, and Firefox is giving me trouble. </p>
  
  <pre><code>&lt;iframe src="" scrolling="no" sandbox=""&gt;&lt;/iframe&gt;
  </code></pre>
  
  <p>I use jQuery to set the iFrame's <code>src</code> attribute to one of several different pages. But my target pages have JavaScript in them that makes them break out of my iFrame. I counter that with the <code>sandbox</code> attribute, which is supposed to prevent JavaScript from running inside the iFrame. This works great in Chrome and Internet Explorer, but in Firefox as soon as I load the target page into the iFrame it takes over the whole window.</p>
  
  <p>Firefox's documentation says it fully supports the <code>sandbox</code> attribute. Am I doing something wrong? Installing NoScript and telling my browser not to run JavaScript from the target site makes everything work fine, but obviously I don't want Firefox users to have to install an addon before my site will work.</p>