Hi kathieochoa,
That is easy enough to do. Add your signature fields (or images) where you want them on the form and set their presence to hidden (or invisible depending on your form structure)
Assuming your listed items in the dropdownlist are: My Signature, Spouse's Signature and Both Signatures.
In the javascript change event for the dropdownlist add this:
if ($.boundItem(xfa.event.newText) == "My Signature") //look in the dropdownlist for this item
{
this.resolveNode("mySignature").presence = "visible"; //show this
this.resolveNode("spouseSignature").presence = "hidden"; //hide this or make invisible using "invisible"
}
else if ($.boundItem(xfa.event.newText) == "Spouse's Signature")
{
this.resolveNode("mySignature").presence = "hidden"; //hide this
this.resolveNode("spouseSignature").presence = "visible"; //show this
}
else if ($.boundItem(xfa.event.newText) == "Both Signatures") //show both signatures
{
this.resolveNode("mySignature").presence = "visible";
this.resolveNode("spouseSignature").presence = "visible";
}