Target format

#firstName
#middleName
#lastName
My Name is #fullname 
        
<bindings>
 <binding source="#firstName" x-model="FirstName" event="input" target="#fullName"
 property="innerHTML" targetformat="{FirstName} {MiddleName} {LastName}" ></binding>

 <binding source="#middleName" x-model="MiddleName" event="input" target="#fullName"
 property="innerHTML" targetformat="{FirstName} {MiddleName} {LastName}" ></binding>

 <binding source="#lastName" x-model="LastName" event="input" target="#fullName"
 property="innerHTML" targetformat="{FirstName} {MiddleName} {LastName}" ></binding>
</bindings>