This hack is DEPRECATED and should not be used due to the imminent release of IE 7. See [the official IE blog] for details.

This CssHack uses a ChildSelector to hide rules from InternetExplorer and other less capable WebBrowser?s. More advanced browsers (MoZilla / OperaSix+ / SaFari ) read the selector correctly.

No invalid CSS is used, and it is quite simple really.

For the HTML fragment:

<body>

<div id="top"> ... </div>

...

#top { ... } will work in pretty much every browsers

but

body > #top { ... } will only work in the better browsers

this can be handy for applying layouts that require FixedPosition, margin:auto or alpha transparent PNGs (or quite a number of other things).