Returning Null Value

Hello, I am working on a simple script and I am getting tripped up at the start.  I'm just trying to confirm that I am getting the correct value from a custom field on my form but my alert keeps returning null.  I can return any other field just fine.  The field I am trying to present is a custom transaction body field of list type and is a list of transactions.  I have selected a value and saved the form but it doesn't seem to recognize it.  Does anyone know what I am missing:

Here is the code:

var oppID = nlapiGetRecordId();