What does *width:auto mean in CSS?

Can anyone please tell me what does

*width:auto;

mean in css?

For example:开发者_StackOverflow中文版

div.ReportingControls dd
{
    width:450px;
    *width:auto;
}

Thanks

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This is a CSS hack for IE. Only IE7 and below will use width auto, instead of 450px;.

Per Microsoft use conditional comments instead of this kind of hack.

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It's a CSS hack to target Internet Explorer 7 and below. And it's not recommended to use in the real world.

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I think it is some kind of trick for browser compatibility as explained in this blog