title: In 'form action="?login"', what does the question mark mean?
body: <p>Consider:</p>
  <pre><code>&lt;form action=&quot;?login&quot; method=&quot;post&quot;&gt;     &lt;button&gt;Login with Google&lt;/button&gt; &lt;/form&gt;
  </code></pre>
  <p>I usually see the <em>action</em> refer to a PHP or HTML file, but the &quot;?login&quot; stumps me.</p>
  <p>Background information:</p>
  <p>This is buried within the <em>example-google.php</em> file from lightopenid framework.  I've been staring at the OpenID code to use Google as a third-party OpenID provider for user login on my web site and the sample code all works.</p>
  <p>I am trying to get a clearer picture of what the framework is doing when the user presses the login button.  I know that we must be sending a bunch of arguments to Google on this button action, but the <code>?login</code> doesn’t seem to point anywhere.</p>
  <p><a href="http://gitorious.org/lightopenid" rel="nofollow noreferrer">http://gitorious.org/lightopenid</a></p>