根据ie浏览器不同的类别选择不同的css

如果是IE浏览器则选择all-ie-only.css

<!--[if IE]>
	<link rel="stylesheet" type="text/css" href="all-ie-only.css" />
<![endif]-->
如果不是ie浏览器则选择not-ie.css

<!--[if !IE]><!-->
	<link rel="stylesheet" type="text/css" href="not-ie.css" />
 <!--<![endif]-->
一下是不同ie浏览器选择的不同css标准
Target only IE 7

<!--[if IE 7]>
	<link rel="stylesheet" type="text/css" href="ie7.css">
<![endif]-->
Target only IE 6

<!--[if IE 6]>
	<link rel="stylesheet" type="text/css" href="ie6.css" />
<![endif]-->
Target only IE 5

<!--[if IE 5]>
	<link rel="stylesheet" type="text/css" href="ie5.css" />
<![endif]-->
Target only IE 5.5

<!--[if IE 5.5000]>
<link rel="stylesheet" type="text/css" href="ie55.css" />
<![endif]-->
Target IE 6 and lower

<!--[if lt IE 7]>
	<link rel="stylesheet" type="text/css" href="ie6-and-down.css" />
<![endif]-->
<!--[if lte IE 6]>
	<link rel="stylesheet" type="text/css" href="ie6-and-down.css" />
<![endif]-->
Target IE 7 and lower

<!--[if lt IE 8]>
	<link rel="stylesheet" type="text/css" href="ie7-and-down.css" />
<![endif]-->
<!--[if lte IE 7]>
	<link rel="stylesheet" type="text/css" href="ie7-and-down.css" />
<![endif]-->
Target IE 8 and lower

<!--[if lt IE 9]>
	<link rel="stylesheet" type="text/css" href="ie8-and-down.css" />
<![endif]-->
<!--[if lte IE 8]>
	<link rel="stylesheet" type="text/css" href="ie8-and-down.css" />
<![endif]-->
Target IE 6 and higher

<!--[if gt IE 5.5]>
	<link rel="stylesheet" type="text/css" href="ie6-and-up.css" />
<![endif]-->
<!--[if gte IE 6]>
	<link rel="stylesheet" type="text/css" href="ie6-and-up.css" />
<![endif]-->
Target IE 7 and higher

<!--[if gt IE 6]>
	<link rel="stylesheet" type="text/css" href="ie7-and-up.css" />
<![endif]-->
<!--[if gte IE 7]>
	<link rel="stylesheet" type="text/css" href="ie7-and-up.css" />
<![endif]-->
Target IE 8 and higher

<!--[if gt IE 7]>
	<link rel="stylesheet" type="text/css" href="ie8-and-up.css" />
<![endif]-->
<!--[if gte IE 8]>
	<link rel="stylesheet" type="text/css" href="ie8-and-up.css" />
<![endif]-->