« XUL Reference
boxObject
Type: nsIBoxObject
This property is available for elements that are derived from boxes, which is most displayable XUL elements. Prior to Gecko 1.9.1, you can retrieve the boxObject for non-XUL elements using the document.getBoxObjectFor method; the method was removed in Gecko 1.9.1 because it was non-standard. It is covered further in the tutorial.