To be more precise: by looking at the response in Firebug's Net panel I see
<h1>Blacklisted for abuse</h1>
<p>
This request has been blacklisted for sending too much traffic to <code>rawgit.com</code>. Please contact the owner of the site that sent you here and ask them to use <code>cdn.rawgit.com</code> instead, which has no traffic limit.
</p>
Nevertheless I wonder if this will work when Firefox's search as you type is enabled. I guess the browser should eat up all those events, but maybe I'm wrong. Can't check it because of the blacklisted script and no time to write my own test now.
<h1>Blacklisted for abuse</h1>
<p> This request has been blacklisted for sending too much traffic to <code>rawgit.com</code>. Please contact the owner of the site that sent you here and ask them to use <code>cdn.rawgit.com</code> instead, which has no traffic limit. </p>
Nevertheless I wonder if this will work when Firefox's search as you type is enabled. I guess the browser should eat up all those events, but maybe I'm wrong. Can't check it because of the blacklisted script and no time to write my own test now.