The z-index property specifies the stack order of an element. An element with greater stack order is always in front of an element with a lower stack order. Note: z-index only works on positioned elements (position:absolute, position:relative, or position:fixed).
Value
Description
(numeric)
If you had 2 absolutely positioned elements that overlapped and you gave element A a z-index value of 5 and element B a z-index value of 10, element B would show in front of element A.
Z-index
The z-index property specifies the stack order of an element. An element with greater stack order is always in front of an element with a lower stack order. Note: z-index only works on positioned elements (position:absolute, position:relative, or position:fixed).
Themeover CSS Reference
Online CSS References: Z-index
Online CSS Tutorials: Z-index