Inferring node placement via special sourceIndex values

I needed to know whether a node was in the DOM. Figuring there was a native property or method towards this end, I scoured Mozilla's documentation but could find nothing. Then Microsoft (yes, them) offered hope with Internet Explorer's sourceIndex property:

Retrieves the ordinal position of the object, in source order, as the object appears in the document's all collection.

sourceIndex (MSDN)

Internet Explorer doesn't bubble click events to the window

This is a simple one. I put some sample code on jsbin.com to show how IE doesn't bubble click events to the window, while w3c browsers do. This is important, because I would normally think to use the window as a "global event listener", not the document. Yeah, I learned this one the hard way.

Internet Explorer sanitizes events between nodes

Events are hard in IE. That is just a fact.

I'm not here to gripe about how IE's event object doesn't adhere to standards, nor offers alternatives. Really, I'm not. This is actually a surprising discovery that has less to do with the standard IE/MS diatribe, and more to do with a unique aspect of their event object.