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Re: Should Document.cloneNode() work in Level 1?

From: John Cowan <cowan@locke.ccil.org>
Date: Wed, 09 Sep 1998 15:05:50 -0400
Message-ID: <35F6D18E.FD75E03B@locke.ccil.org>
To: DOM List <www-dom@w3.org>
Stephen R. Savitzky wrote:

> It is reasonable to expect that cloneNode will copy _everything_ that it is
> meaningful to copy

I have no such expectations.

> (and it is certainly possible to ensure this for any
> particular implementation).


> One could even write this requirement into the
> specification.

"*One* can't, perhaps, but *two* can."
	-- Humpty Dumpty

But at any rate, four (the authors of the DOM Core PR) did not.
The PR says only:

# Returns a duplicate of the node, i.e., serves as a generic copy
# constructor for Nodes. The duplicate node has
# no parent (parentNode returns null.).
# Cloning an Element copies all attributes and their values,
# including those generated by the XML processor to
# represent defaulted attributes, but this method does not
# copy any text it contains unless it is a deep clone, since
# the text is contained in a child Text node. Cloning any
# other type of node simply returns a copy of this node. 

> On the other hand, it is clearly impossible to do this with the createXXX
> methods -- that's why cloneNode exists in the first place.

I believe cloneNode to be a convenience method.  Everything it does
can be done with:

	switch (this.nodeType) {
	case ELEMENT_NODE: new = this.ownerDocument.createElement(...)
	case TEXT_NODE: new = this.ownerDocument.createText(...)
	etc. etc.
John Cowan	http://www.ccil.org/~cowan		cowan@ccil.org
	You tollerday donsk?  N.  You tolkatiff scowegian?  Nn.
	You spigotty anglease?  Nnn.  You phonio saxo?  Nnnn.
		Clear all so!  'Tis a Jute.... (Finnegans Wake 16.5)
Received on Wednesday, 9 September 1998 15:07:36 UTC

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