My preference is use a Text Field object and script to do validation. This may not be for everyone. I defined a Text Field called 'tf' with a maximum character length of 9 and added the script below to the exit event.
// form1.page1.tf::exit - (JavaScript, client)
if (!(this.isNull)) {
var tf = this.rawValue;
var regExp = /^\d{9}$/;
if (regExp.test(tf)) {
if (tf.substr(0,1) != "1") {
xfa.host.messageBox("The field must be start with a 1.","Validation",1);
}
}
else {
xfa.host.messageBox("The field must be 9 digits starting with a 1.","Validation",1);
}
}