breaking on jscript runtime error permission denied

[Julian]

I am trying to learn JavaScript working with Jeremy Keith's book "DOM
Scripting". I have written a function (below) as a way of
understanding better about nodes. This works fine on FireFox -
although it never finds attribute (type 2) nodes! On IE8 , when it
gets to "if (node.nodeType == 1)" it throws up the "Permission Denied"
error and the script stops. I'm beat. Can anyone help me, please.
Thanks. And why do type 2 nodes not show up?
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var depth = 0;
function family(node,count) {
// indents
for (var i = 0; i < depth; i++)
document.write("&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;");

// start writing about this element
document.write(depth + "/" + count + ": Element is type = " +
node.nodeType + ", name = " + node.nodeName + ", ");

// if it's tag show tagname else show value
if (node.nodeType == 1) {
document.write(" tag = &lt;");
document.write(node.tagName);
document.write("&gt;");
}
else {
document.write("value = '" + node.nodeValue + "'");
}

// if there are any children
if (node.hasChildNodes) {

// get the children
var cn = node.childNodes;

// tell us how many
document.write(". The element has " + cn.length + " child")
if (cn.length > 1) document.write("ren");
document.write(".<br />");

// process the children
depth++;
for (var c = 0; c < cn.length; c++) {
family(cn[c],c);
}
depth--;
}
else {
document.write(".<br />");
}
}
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