Arran Mccullough added a comment - 02/Aug/11 4:39 PM Dev comments on cause of issue: The error occurs here where it tries to get the tagName of the passed in element: This.Element.adaptToElement = function(e) { //no polymophism here...'switch' is the way then. if (!e) return new This.Element(e); switch (e.tagName.toLowerCase()) { case 'textarea': case 'input': return new This.InputElement(e); case 'thead': case 'tfoot': case 'tbody': case 'th': case 'td': case 'tr': return new This.TableCellElement(e); case 'button': return new This.ButtonElement(e); case 'select': return new This.SelectElement(e); case 'form': return new This.FormElement(e); case 'body': return new This.BodyElement(e); case 'script': return new This.ScriptElement(e); case 'title': return new This.TitleElement(e); case 'a': return new This.AnchorElement(e); case 'iframe': return new This.IFrameElement(e); default : return new This.Element(e); } }; Not sure why Chrome would have an issue with this compared to the other browsers. If I debug it a bit, it seems that during processing, the event.source is determined to be an HTMLDocument (which I guess makes a certain sense for the onload) but in Chrome, the HTMLDocument does not have a tagName attribute and this is what causes the exception to be thrown. I guess a fix would be to check for e.tagName and just return This.Element(e) for that as well: This.Element.adaptToElement = function(e) { //no polymophism here...'switch' is the way then. if (!e) return new This.Element(e); if (!e.tagName) return new This.Element(e); switch (e.tagName.toLowerCase()) { case 'textarea':

Arran Mccullough added a comment - 02/Aug/11 4:39 PM Deryk's correct, the event's 'srcElement' property is the HTMLDocument which does not have a 'tagName' property. A simpler solution that has been adopted lately is to use the 'nodeName' property instead because it always returns a string for any type of DOM node: ... switch (e.nodeName.toLowerCase()) ...

Mircea Toma added a comment - 03/Aug/11 4:35 PM Use Node.nodeName property to acquire the element's tag name, in case the passed in node does not have a tag name the 'nodeName' will still return a non-null name.