sstephenson/prototype — pull request #99 by lunich (2013-03-05 15:23:44+00:00)
Title: IE7 bugfix for getOffsetParent if non-inline element with offsetParent==HTML

Sometimes in IE7 there element.offsetParent return HTML element. In this case it's makes sense to check if offsetParent is HTML element and return document.body if so.
The same method used for nearest parent node with position !== 'static'.