Trubar
 Ordinary keys

They are defined in input forms as names of fields. Example:

   <form method=post action="URL">
   Name: <input type=text name=name><br>
   Age: <input type=text name=age><br>
   Sex: <input type=radio name=sex value=m> Male
   <input type=radio name=sex value=f> Female<br>
   Address: <input type=text name=address><br>
   <input type=submit value="Submit">
   </form>

Name:
Age:
Sex:	Male Female
Address: