Javascirpt that creates hover over button

Hello,

I am new to this forum and I have no experience with Javascript, So I might be asking the wrong questions in the wrong place. I am trying to work out a)if it possible and b) how do I go about find resource to do it.

I have a pdf drawing with coded text. (eg DR01 which standard for a SOLID FIRE DOOR) This requires the reader to constantly refer to the legend (which may be a different document) to understand what they are looking at. I want to use a CSV file with a list of CODEs, DESCRIPTIONs to be read by the javascript script. The script will then search for each of the CODEs in the PDF and create a button (with no border or fill) at every location where the CODE occurs and it will show the DESCRIPTION as you hover over it.

I thank you all in advance.