z-index

This attribute takes numeric values - positive or negative - or the default value of auto. The attribute setting affects the manner in which successive elements in an HTML document are displayed. We have discussed this subject at length elsewhere.

This is not an inherited property - i.e. in a child element, if not assigned, it takes the default value rather than the corresponding value in its parent container.

This attribute can also be assigned the setting inherit which causes it to pick up its value from the parent element.