Order of DOM NodeList returned by getChildNodes()

Question

The DOM method getChildNodes() returns a NodeList of the children of the current Node. Whilst a NodeList is ordered, is the list guaranteed to be in document order?

For example, given <a><b/><c/><d/></a> is a.getChildNodes() guaranteed to return a NodeList with b, c and d in that order?

The javadoc isn't clear on this.

Answer 1

In my experience, yes. The DOM spec isn't any clearer. If you're paranoid, try something like

current = node.firstChild;
while(null != current) {
    ...
    current = current.nextSibling;
}

Answer 2

A document-ordered node list is the behavior in other implementations of the DOM, such as Javascript's or Python's. And a randomly-ordered node list would be utterly useless. I think it's safe to depend on nodes being returned in document order.

Answer 3

My experience is that every time that I have bothered to look it has been in document order. However, I believe that I read somewhere it is not guaranteed to be in document order. I can't find where I read that right now, so take it as hearsay. I think your best bet if you must have them in document order would be to use FirstChild then NextSibling until there are no more sibs.

Answer 4

I'd love to tell you that this is guaranteed (as I believe it is) but the Document Object Model specification itself seems ambiguous in this case. I'm pretty sure that it's always document-order, though.

Answer 5

In your example, as presented. I believe so. However, I've experienced real-world experiences where spaces have been interpreted as nodes so:

<a><b/><c/><d/></a>

is different than

<a><b/> <c/><d/></a>

if you're looking at index [1], firefox and IE may present different results. I would advise against relying on the order depending on your need.

Answer 6

Yes they are ordered as it returns a nodeList, you would have to say getNamedChildNodes to get a list that is not ordered as in namedNodeList.