2017
CSS - Z-INDEX - What No One Told You About Z-Index — Philip Walton
The problem with z-index is that very few people understand how it really works. It’s not complicated, but it if you’ve never taken the time to read its specification, there are almost certainly crucial aspects that you’re completely unaware of.
2014
CSS - Online Demo Interactive - CSS 101: z-index PlayGround
What to do with these boxes?
The six colored boxes (A, a, B, b, C, c) are "draggable", which means you can use your mouse to position them anywhere in the page.
The input elements in the colored fieldsets let you set z-index and position values for each one of these six boxes. These fieldsets are color coded, which means a fieldset's background color matches the background color of the box it is supposed to style.
Use Firebug to monitor in real time how these elements get styled.
1
(2 marks)