JavaScript validation to format tax id field based on check box value.

I have an Adobe form, please see attached. I have a Radio Button called SSNEIN for the user to select if they have a Social Security Number or an Employer Identification Number. Then I want them to enter the number, and automatically format it based on the selection (SSN or EIN). In Actions, On Blur, Run a JavaScript, I have:

f = getField(event.target.name)
if (f.value.length == 0)
{
f.setFocus()
app.alert("This field is required. Please enter the Social Security or Employer Identification Number of Primary Owner.")
}

In Validate, Run custom validation script, I have:

if (event.value)
{
if (/^\d{9}$/.test(event.value)==false && (/^\d{2}\-\d{7}$/.test(event.value)==false && (/^\d{3}\-\d{2}\-\d{4}$/.test(event.value)==false)))
{
app.alert("You entered an Invalid Tax ID Number. It must contain only numbers without dashes or numbers with the dashes in the correct position(s}.",1); event.rc = false;
}
}

// Format as Social Security Number or EIN
var Q = this.getField("SSNEIN");
if(Q == "SSN")
{
if (event.value)
{
event.value = util.printx("999-99-9999", event.value);
}
else

{
event.value = util.printx("99-9999999", event.value);
}
}

The On Blur works. Where it checks for a valid set of characters works. The last part does not work. It does nothing. No errors, just doesn't work. Can you tell me where I went wrong? Thank you very much.