Adding a button to run a script on viewing a sales order

I'm having troubles trying to get this to work... I will preface this post by saying that I'm a beginner with scripting.  I've been able to do some decent form level client scripts, but this problem I haven't been able to solve yet.

I was able to add a button to the Sales Order view event and assign it a script, but the way I added the script is preventing most of the code from working.

The following code below is the contents of a javascript file called CopyMonthlyServicesSalesOrder.js which I've used to create a User Event script called customscript_copymonthlysalesorder which loads the myBeforeLoadFunc function.  It successfully adds the button to the sales order while being 'viewed' and when the button is clicked it will successfully display the test alert with the record type and id. The problem is when I try to do anything else with the script like either: alert(nlapiGetFieldValue('custbody_renewal')); or alert(curRecord.nlapiGetFieldValue('custbody_renewal')); that nothing happens.