Getting ID of collapsed div, in Toggle event
<p>I have multiple divs setup, with headers and content.
When you click the header, it expands the content on the selected div, and hides all others.
This works fine, but I need to get the ID's of all the content divs, that have been hidden or shown.</p>

<p>This is my jquery for the hide/show:</p>

<pre><code>$(".CollapsableHeader").next(".CollapsableDiv").hide();
            $(".CollapsableHeader").click(function () {
                $('.active').not(this).toggleClass('active').next('.CollapsableDiv').slideToggle(300, function () {
                    alert($(this).next('.CollapsableDiv').attr('id'));
                });
                $(this).toggleClass('active').next().slideToggle("fast");

            });
</code></pre>

<p>So, in this example, my alert always comes up as, <code>undefined</code>.
Everything I have tried, comes up as <code>undefined</code>. 
Any idea how I can get the ID's of the <code>.CollapsableDiv</code>'s?</p>
