iframe variables in php
<p>I've got an iframe that is sending variables in the url.  Problem is I've got 2 variables that is being send in the url, when I echo the first variable, it also displays the value of the 2nd variable:</p>

<p><strong>PAGE1</strong></p>

<pre><code>&lt;?php
$tid = $_SESSION['tid'];
$userid = $_SESSION['userid'];
echo "&lt;IFRAME SRC='timer.php?tid=$tid?userid=$userid' WIDTH='500' HEIGHT='500' frameborder='0'&gt;&lt;/IFRAME&gt;";
</code></pre>

<p><strong>TIMER.PHP</strong></p>

<pre><code>session_start();
$tid = $_GET['tid'];
echo "tid:";
echo $tid;
</code></pre>

<p><strong>OUTPUT:</strong>  </p>

<pre><code>tid:8?userid=999
</code></pre>

<p><em><strong>The output should only be tid:8</em></strong> why the ?userid=999</p>
