Relative lets you specify the box's position in the layout relative to its default position, so other boxes still affect its final position. Absolute lets you specify the box's precise position in the layout according to the box's containing block , so other boxes cannot affect its position. The position property allows a Web browser to process the top and left properties.
Some browsers skip the top and left properties if the boxes have the default position value.
To make sure that the browser processes the top and left properties, the position value of the boxes must be set to relative.