Adding methods to Node or Element objects?

[Weston C]

I'm wondering if it's possible to add a method to the Node and/or
Element objects (so they'd subsequently be available to any
node/element). I'd assume you could just do something like:

n.myNewMethod = function myNewMethod;

where n is any Node -- but the fact that Nodes and Elements are
explicitly definied as interfaces rather than actual objects in the DOM
standard makes me wary. Javascript/ECMAscript, iirc, however, uses a
prototype object-oriented model that doesn't have interfaces, right?

Thanks,
Weston



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[Lasse Reichstein Nielsen]

Re: Adding methods to Node or Element objects?

Weston C <west8on[at]cann8central.Re moveEights.org> writes:
[color=blue]
> I'm wondering if it's possible to add a method to the Node and/or
> Element objects (so they'd subsequently be available to any
> node/element). I'd assume you could just do something like:[/color]

Not generally.
In Mozilla, you can use
Node.prototype. myNewMethod = function (...){...};
Other browsers don't have the constructor function for nodes available.
[color=blue]
> Javascript/ECMAscript, iirc, however, uses a prototype
> object-oriented model that doesn't have interfaces, right?[/color]

Yes. There is no requirement in the W3C DOM that the ECMAScript binding
makes constructors available. You have the factory methods on the document
object if you need to create elements.

/L
--
Lasse Reichstein Nielsen - lrn@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'

[Grant Wagner]

Re: Adding methods to Node or Element objects?

Weston C wrote:
[color=blue]
> I'm wondering if it's possible to add a method to the Node and/or
> Element objects (so they'd subsequently be available to any
> node/element). I'd assume you could just do something like:
>
> n.myNewMethod = function myNewMethod;
>
> where n is any Node -- but the fact that Nodes and Elements are
> explicitly definied as interfaces rather than actual objects in the DOM
> standard makes me wary. Javascript/ECMAscript, iirc, however, uses a
> prototype object-oriented model that doesn't have interfaces, right?
>
> Thanks,
> Weston[/color]

Sure, the following works in Gecko based browsers (Mozilla Firebird,
Mozilla, Netscape 7.x, Camino):

<div id="blah"></div>
<div id="bleh"></div>
<script type="text/javascript">
HTMLDivElement. prototype.myId = function() {
alert(this.id);
}
</script>
<button onclick="docume nt.getElementBy Id('blah').myId ();">blah</button>
<button onclick="docume nt.getElementBy Id('bleh').myId ();">bleh</button>

I figured out how to this here: <url:
http://www.mozilla.org/docs/dom/mozilla/protodoc.html />

For most other browsers you'll just have to assign the method to all the
elements of that type at run-time:

<div id="blah"></div>
<div id="bleh"></div>
<script type="text/javascript">
var divs = document.getEle mentsByTagName( 'div');
if (divs != null) {
for (var i = 0; i < divs.length; i++) {
divs[i].myId = myId;
}
}
function myId() {
alert(this.id);
}
</script>
<button onclick="docume nt.getElementBy Id('blah').myId ();">blah</button>
<button onclick="docume nt.getElementBy Id('bleh').myId ();">bleh</button>

--
| Grant Wagner <gwagner@agrico reunited.com>

* Client-side Javascript and Netscape 4 DOM Reference available at:
*

http://devedge.netscape.com/library/manuals/2000/javascript/1.3/reference/frames.html

* Internet Explorer DOM Reference available at:
*

http://msdn.microsoft.com/workshop/author/dhtml/reference/dhtml_reference_entry.asp

* Netscape 6/7 DOM Reference available at:
* http://www.mozilla.org/docs/dom/domref/
* Tips for upgrading JavaScript for Netscape 7 / Mozilla
* http://www.mozilla.org/docs/web-deve...upgrade_2.html