How do I pass a dynamically created form field to another page through an href query string or on Click method

Hi.  I'm updating an older website that is still using Classic Asp (so please no asp.net answers thanks!)  I'm working with a page where my form fields are dynamically named from a record source.   The user will click on a button or link that will pop up my other page in a new window (specific size) and all i need to know in the new window is what record or row they clicked on.  There are quite a few different ways I see to do this but I'm not sure how to pass my field name variable and value properly within javascript needed to open a new sized pop up window.  For example.. i have ..

<input type="hidden" name="<%=RecFldNm%>" value="<%=vPRecID%>">
<input type="button" name="<%=AddBtn%>"  value="Add">

So..  if I have 3 rows displayed from my record set, I end up with 3 sections on my form with each item named... (source view)

<input type="hidden" name="RecFldNm1" value="39471" >
<input type="button" name="AddBtn1"  value="Add">
<input type="hidden" name="RecFldNm2" value="39472" >
<input type="button" name="AddBtn2"  value="Add">
<input type="hidden" name="RecFldNm3" value="39473" >
<input type="button" name="AddBtn3"  value="Add">

I have no problem getting everything I need when posting the form to my asp code page etc.  My problem here is that I want the user to click on one of the "Add" buttons (or it can be a hyperlink etc.) that opens another page in a new window that is sized that allows them to add some things.  If the user chooses the 2nd record, i want to be able to pass 39472 record id, value of my hidden field RecFldNm2 to the new page or even know that they clicked on AddBtn2.  I can work with either way.. i'm just not sure how to pass the value.

Thanks for any help!