Most CSS properties are quite simple to deal with. Often, applying a CSS property to an element in your markup will have instant results — as soon as you refresh the page, the value set for the property takes effect, and you see the result immediately. Other CSS properties, however, are a little more complex and will only work under a given set of circumstances.
z-index property belongs to the latter group.
z-index has undoubtedly caused as much confusion and frustration as any other CSS property. Ironically, however, when
z-index is fully understood, it is a very easy property to use, and offers an effective method for overcoming many layout challenges.
In this article, we’ll explain exactly what
z-index is, how it has been misunderstood, and we’ll discuss some practical uses for it. We’ll also describe some of the browser differences that can occur, particularly in previous versions of Internet Explorer and Firefox. This comprehensive look at
z-indexshould provide developers with an excellent foundation to be able to use this property confidently and effectively……