The type property returns the type of the select box. This is either select-multiple, if the multiple attribute is set in the tag, or select-one if it is not.
<html> <head> <script language="JavaScript1.1"> <!-- function getType(){ alert("The name of this text box is " + document.myForm.elements[0].type); } --> </script> </head> <body> <form name="myForm"> <select name="mySelect"> <option value=A>AA</option> <option value=B>BB</option> <option value=C>CC</option> <option value=D>DD</option> </select> <input type=BUTTON value="Get Type" name="myButton" onClick='getType()'> </form> </body> </html>