Dynamic Submit Button- Required Fields

I needed a dynamic submit button that would cc a field from the form.  I found the following script and it works great, but it doesn't give an error message if someone didn't fill in a required field like a regular submit button would. Is it possible to use the script below but to check for required fields?

// This is the form return e-mail. Its hardcoded

// so that the form is always returned to the same address

// Change address on your form

var cToAddr = "909@gideons.org";

// First, get the client CC e-mail address

var cCCAddr = RegionalDirector;

// Set the subject and body text for the e-mail message

var cSubLine = "909 Camp Visitation Report-" + xfa.resolveNode("#subform[0].#subform[7].Country"); var cBody = "Thank you for submitting your 909 report.\n" + "Save a copy for your records";

// Send the form data as an FDF attachment on an e-mail

event.target.mailDoc({

          bUI: true,

          cTo: cToAddr,

          cCc: cCCAddr,

          cSubject: cSubLine,

          cMsg: cBody

});