Empty variable passed in URL
<p>I am passing a variable in a URL from create_topic.php, but the variable is empty.  The page passing the variable uses that variable in a mysql query OK, so I know that its not empty then, but when I click a link in that page to go to another page, the variable is not being passed.</p>

<p>in create_topic.php I have:</p>

<pre><code>$author_pk = $_GET['author_pk'];
</code></pre>

<p>Then in the query on that page:</p>

<pre><code>$query = "INSERT INTO topic (topic_pk,title,topic,majors,sub_discipline_fk,author_fk,created,place)
  VALUES ('','$title','$topic','$majors_string','$sub_discipline','$author_pk',NOW(),'$place')";
$result = mysql_query($query, $connection) or die(mysql_error());
</code></pre>

<p>$author_pk contains the passed value OK.</p>

<p>But in a link in create_topic.php I have:</p>

<pre><code>&lt;a href="create_author.php?author_pk="&lt;?php echo $author_pk; ?&gt;&gt;Create&lt;/a&gt;
</code></pre>

<p>$author_pk is then empty in the URL...</p>
