5 Appendix C: hasLayout
To optimize layout, elements in Quirks Mode and IE7 Mode fall into one of the following categories:
The element is responsible for sizing and positioning all of its content and that of its child elements. It has layout by default.
The element is reliant upon an ancestor element for sizing and positioning and does not have layout.
The hasLayout property is a Document Object Model (DOM) property that indicates when an element has a layout. It is used internally only in quirks mode and IE7 mode to implement CSS positioning. It is not used at all in IE8 mode or IE9 Mode.
The property is true when:
An element has layout by default
The property of an element that does not have layout by default is assigned a value. Resetting the property value to the element’s default value resets the value of hasLayout to