'undefined' error on first custom JavaScript

I'm trying to add my first custom JavaScript to a form field.  I added this source code as a Web Resource to my custom solution:

function nmc_setSuppItemSubmissionDate() {
   debugger;
   var submissionStatus = Xrm.Page.getAttribute("datatel_submissionstatus").getValue();
   var submissionDate   = Xrm.Page.getAttribute("datatel_submissiondate").getValue();
   
   if (submissionStatus == "Received" || submissionStatus == "Waived" || submissionStatus == "Approved") {
      if submissionDate == "" {
         var currentDateTime = new Date();
         Xrm.Page.getAttribute("datatel_submissiondate").setValue(currentDateTime);
      }
   }
   else {
      Xrm.Page.getAttribute("datatel_submissiondate").setValue(null);
   }

In the list of Web Resources, it has a Display Name of SetSupplementalSubmissionDate and a Name of nmc_setSubmissionDate.

I then went into the:

• Form Properties Events tab and added nmc_setSubmissionDate to the Form Libraries
• Field Properties Events tab of the datatel_submissionstatus field and added the library nmc_setSubmissionDate and function nmc_setSuppItemSubmissionDate 
  to the OnChange event

I saved and published the form.  When I change the datatel_submissionstatus field in the form, I get the error:

There was an error with this field's customized event:  Field: datatel_submissionstatus  Event:onchange
Error:'nmc_setSuppItemSubmissionDate' is undefined.

I'm not sure what I'm doing wrong.  If anyone could explain this, I would be grateful.