Script needed

I have a text field with limit characters 6 digits and on exit event the validation below:

if (this.rawValue.length < 6)
{
app.alert("This field requires 6 digits");
xfa.host.setFocus(this); }

This I like to achive is when the first 3 digits of the 6 starts with 333 I"ll like to genarate
the value: xxx [at] xxx [dot] com into a textField named EmailAddress.
In case there is any other number compinazation than starting with 333 EmailAddress value to be
empty!

Is this possible?

Thnk you