Collapse-O-Matic is a WordPress plugin. But what if you wanted to use it on a static HTML page?
Well, that just might work.
Step 1: make sure jQuery is installed
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
Step 2: install collapse.js
You will need to download the latest version of Collapse-O-Matic and then find and upload just the collapse.js file. It’s located in the js sub-folder.
<script src="http://yourdomain.com/path_to_js/collapse.js"></script>
Step 3: Use the Roll-Your-Own Method
Now that you have all the jQuery scripts installed, you can simply follow the standard roll-your-own method to create the expand elements.
Good luck!