Try setting the text field format to Rich Text (for object go to Object tab > Field tab > Field Format:).
Additionally, the following script concatenates two fields into one where the script is attached to the calculate event of the target field.
// form1.page1.subform1.fullName::calculate - (JavaScript, client)
if (form1.page1.subform1.firstName.isNull) {
this.rawValue = form1.page1.subform1.lastName.rawValue;
}
else {
if (form1.page1.subform1.lastName.isNull) {
this.rawValue = form1.page1.subform1.firstName.rawValue;
}
else {
this.rawValue = form1.page1.subform1.firstName.rawValue + " " + form1.page1.subform1.lastName.rawValue;
}
}
Steve