If 'display' has the value 'none', user agents must ignore 'position' and 'float'. In this case, the element generates no box.
This rule is tested in my test of
Otherwise, 'position' has the value 'absolute' or 'fixed', 'display' is set to 'block' and 'float' is set to 'none'. The position of the box will be determined by the 'top', 'right', 'bottom' and 'left' properties and the box's containing block.
div, underneath the three absolutely positioned boxes (one at the left, one centered, and one at the right). First absolutely positioned
span. Second absolutely positioned
span. Third absolutely positioned
Otherwise, if 'float' has a value other than 'none', 'display' is set to 'block' and the box is floated.
Otherwise, the remaining 'display' properties apply as specified.
See all my other tests for various display properties.
(Back to CSS Testing Information, David Baron)