Drop Down List items based on text box input

I want to create a drop down list but the list items are unknown until the recipient of the form completes the first page.  

On page 1 of a PDF form I have rows/columns of text boxes.

On page 2 I would like drop down lists where the items are taken from the text box input of column 1 on page 1. 

I know that you can "Allow User to Enter Custom Text" in the options of the drop down list but I would like to remove user input error and the need to copy and paste from previous fields. 

I think it will involve javascript but I can't find guidance from someone who has done this before? I can't be the first person to need this!

Thanks