assigned → closed
The only reasonable solution to solving this is to copy innerHTML from the source element into the clone element. Since we only want to do this when a non-native element (ie. HTML5 nodes are not native in oldIE) appears as a child of the element being cloned. To do this, we need to look at all of the children of the element being cloned and check if any have a nodeName that matches the known and supported HTML5 nodeNames. If any of those children have children themselves, then we need to traverse downward and run the same check on all of those children (and of course, so on down through all children). When the nest is only one or two branches deep, with a only a handful of children, this will work just fine. The problem comes when there are very deeply nested DOM trees with large children counts. In those cases, this approach becomes unrealistic.