How can I best track multiple selections before submitting a form?

I have a page that lists a bunch of items in divs. This list is generated dynamically from a database. My question is two-fold. First, I would like to know how I can click on multiple divs and somehow store the values so I can then insert the data at the end of the page.

Example:

<div id=add>Item Number A</div>
<div id=add>Item Number B</div>
<div id=add>Item Number C</div>

When any div is clicked, a footer appears fixed to the bottom of the screen with an "add selected" button that, when clicked, will insert all selected values into my database.

The main issue I have right now is how to grab and store the values of the clicked divs.

The second part of the question is, if there is a better way of doing this, please let me know.

Thanks in advance.