I've spent half the evening trying to answer the question: Why the fuck don't I get an offsetParent with this goddamn element???The answer proved to be quite simple... I was hiding the div-element containing the element I was reading the offset value of, before reading the values. These values are erased when you set display: none;I was using a window-like javascript which would hide other windows and then place a new window at the element I clicked on. I didn't realize this method would botch when I wanted to click on a helpbutton inside one of those windows.Another evening well spent. Grmbl. Luckily I spent most of it watching tv and chatting ;)