The id of the html element which should be collapsed is used for the script code to toggle the visibility.
Given our spec reads like this:
<div id="id" class="collapsible">This should be collapsible.</div>
When run the id is passed as parameter to the javascript function:
javascript:Collapsible.collapseExpand('id');
Given our spec reads like this:
<div class="collapsible">This should be collapsible. With a generated id on the element.</div>
When run an id is generated and used as parameter to the javascript function:
<div class="toggleContainer">
<a href="javascript:Collapsible.collapseExpand('1409716573');">Expand / Collapse</a>
<div class="collapsible" id="1409716573" collapsed-height="1.5" collapsed-height-unit="em" style="height: 1.5em;">This should be collapsible. With a generated id on the element.</div>
</div>