For more context around this demo, visit: http://welcome.totheinter.net/2009/07/21/the-undocumented-life-of-javascripts-parentnode-property-internet-explorer-edition/.
Even though the javascript code on this page doesn't call removeChild(), the node below still only exists once in this document. It does not have 2 parents. You should see only 1 "one of me?!" nodes below:
one of me?!