Not possible without looping.  However, if there're no interlaced
link or input control from another form within this form, and if you 
didn't
change the tabbing order, maybe tabIndex property can give you some 
hint.
http://www.w3.org/TR/2000/WD-DOM-Level-1-20000929/level-one-html.html#ID
-604
3025
> -----Message d'origine-----
> De=C2=A0: chandrabhan_dutta [mailto:chandrabhan_dutta@i...]
> Envoy=C3=A9=C2=A0: vendredi 27 d=C3=A9cembre 2002 07:26
> =C3=80=C2=A0: javascript
> Objet=C2=A0: [javascript] Form object
>
>
> Hi all,
>
> Form object has a collection called elements. one can access
> the fourth form element by giving document.frm.elements[3].
> Is it possible to find the reverse, that is, number if a form
> element is known without looping through?
>
> Suppose I have an object document.frm.chkbox. Now I want to
> know, at which index of document.frm.elements this object occurs.
>
> Regards,
> Chandrabhan Dutta Majumdar