Dynamicallu Updatable Floating "menu Like" Layer

Im looking for an advise on where to begin with something I need to accomplish using JavaScript/Ajax on classic ASP platform.

I need to add a floating menu like layer to the site that contains user selected information from the page. So for example, a page has blocks of information organized in a tabular fashion - a lots of them. Each block has a heading containing a check box. This check box serves as a marker that picks the particular item. When the pick is made, a floating status layer is updated with the pick. In this floating layer there is also a submit button that can be click when the user is done with selection.

There is page I've come across that has something similar to what I need to accomplish but I don't know what technology is used. If you go to this site [url] you'll see in the middle of the page several blocks of different items each with green heading titled "Add to request list" containing a check box. As soon as you click the check boxes a separate area called "Your Request List" is populated with some data.