Start:

OK, here's a small guide how to make a boxes/layers collapsible. Let's say, you have a simple div-container you want to make collapsible. The css ids and classes assigned to the elements are completely arbitrary.


<div id="test" class="anything">
<h2 class="blockhead">
<span>Collapse it!</span>
</h2>
<div class="blockrow">
<p>Let's add a button to collapse this box :-)</p>
</div>
</div>



Step 1: Adding "collapse"-class to surrounding container

<div id="test" class="anything collapse">The next line in the example establishes the container's header, in this case by means of a level 2 heading. This header will not be collapsed with the rest of the box but remain visible. This line can be left untouched.


Step 2: Adding id to what we want to hide

As a second step we have to add an unique id to the element that contains what we want to dissapear. Note: This element can be almost any html-tag that can be hidden (div, ul, ol, p, a - you get the idea). Note also: The element has to have an id that needs to be unique not only on the page, but on the whole site. So make sure you use some unique prefix, suffix or something like that (marked in blue).

<div class="blockrow" id="cel_dummy">


Step 3: Adding collapse-button
Inside the header add the code for the collapse-button. You'll have to adapt it according to the id you assigned in step 2 (adaptions needed marked in blue). Make sure the part you add inside the image name variable is not the exact same as the id you added to the container that you want to hide. If you add the exact same, the button will vanish under certain circumstances, too:

<a class="collapse" id="collapse_cel_dummy" href="{vb:raw relpath}#top"><img src="{vb:stylevar imgdir_button}/collapse{vb:raw vbcollapse.collapseimg_cel_dummy_img}_40b.png" alt="{vb:rawphrase collapse_this_category}" /></a>


Result:

In the end, the code will look like that:

<div id="test" class="block collapse">
<h2 class="blockhead">
<span>Collapse it!</span>
<a class="collapse" id="collapse_cel_dummy" href="{vb:raw relpath}#top"><img src="{vb:stylevar imgdir_button}/collapse{vb:raw vbcollapse.collapseimg_cel_dummy_img}_40b.png" alt="{vb:rawphrase collapse_this_category}" /></a>
</h2>
<div class="blockrow" id="cel_dummy">
<p>Let's add a button to collapse this box :-)</p>
</div>
</div>


Collapsed as default? Yes, but...

There is a way default the box to be collapsed by default. But this it's quick and dirty, and really not recommended to use. Basically, you have to add display:none to the style of the collapsing container, like so:

<div class="blockrow" id="cel_dummy" style="display: none;">Now, there are two major drawbacks:
any user with javascript disabled will not be able to open the box, and the box will show the wrong icon.
vB at this point only saves information on closed boxes to a cookie; so if you reload the page, the box will always be closed, because vB will not remember that it has been opened.

Collapse more than one box at a time? Yes, but...

Now, functionally this is perfectly possible - just use the same id for every element you want to collapse together. But beware: for valid code you can't use duplicate ids on a page. So if you do that, your code will break xhtml validation!

I hope this will be useful for some of you!
-c

Please note that this article has been written first for alpha 1 version and been updated for beta 3. There still may be changes until gold. For example the button used is clearly marked as beta (_40b in the file name).