document.documentElement.ownerDocument

Let's print the node name (tag name), so it's easier to detect which node it is. You should get HTML as an answer. For printing the root's properties, always go the root node by using the documentElement property. The printing above is actually done via:

alert(document.documentElement.ownerDocument.documentElement.nodeName);

Now, let's go deeper in the tree, to document's first child (HEAD):

document.documentElement.firstChild

And then let's go directly back to the root of the DOM tree:

document.documentElement.firstChild.ownerDocument

As previously, let's print the node name of the root. Again, we go to the root node by the documentElement property:

alert(document.documentElement.firstChild.ownerDocument.documentElement.nodeName);

You should get HTML.

The code in this tip can be viewed only by Netscape 6.

Learn more about the DOM in Columns 40, The DOM, Part I: Analysis, through Column 47, A DOM-Based Snakes Game, Part II.

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