Subj : Re: Looking for standards document
To   : netscape.public.mozilla.jseng,netscape.public.mozilla.dom
From : Martin Honnen
Date : Mon Mar 07 2005 03:51 pm

Crosspost/followup-to netscape.public.mozilla.dom.

sukhisoul@yahoo.com wrote:


>     We have noticed that most browsers allow an element of
> a form to be accessed as follows:
> 
>     document.forms[0][0]
> 
>     Basically, double-indexing forms array gives corresponding
> element of elements array of that form.


>     Can somebody refer me to the standards document that
> mandates this? 

The W3C DOM Level 2 HTML module should cover this, document.forms is 
defined here
   <http://www.w3.org/TR/DOM-Level-2-HTML/html.html#ID-1689064>
as a HTMLCollection which is defined here
   <http://www.w3.org/TR/DOM-Level-2-HTML/html.html#ID-75708506>
as having two methods item and namedItem. For JavaScript the ECMAScript 
binding is relevant which says here
   <http://www.w3.org/TR/DOM-Level-2-HTML/ecma-script-binding.html>
   "item(index)
     This function returns an object that implements the Node interface.
     The index parameter is a Number.
     Note: This object can also be dereferenced using square bracket 
notation (e.g. obj[1]). Dereferencing with an integer index is 
equivalent to invoking the item function with that index."

Thus at least
   document.forms[0]
is part of the W3C DOM standard.

The shortcut
   document.forms[0][0]
for
   document.forms[0].elements[0]
is not formally specified I think but has traditionally been possible in 
the browser DOM ever since forms have been exposed to script.

-- 

	Martin Honnen
	http://JavaScript.FAQTs.com/

.