Css:Conditional comments 条件注释

http://msdn.microsoft.com/en-us/library/ms537512(VS.85).aspx

http://www.quirksmode.org/css/condcom.html

Item Example Comment
! [if !IE] The NOT operator. This is placed immediately in front of the feature, operator, or subexpression to reverse the Boolean meaning of the expression.
lt [if lt IE 5.5] The less-than operator. Returns true if the first argument is less than the second argument.
lte [if lte IE 6] The less-than or equal operator. Returns true if the first argument is less than or equal to the second argument.
gt [if gt IE 5] The greater-than operator. Returns true if the first argument is greater than the second argument.
gte [if gte IE 7] The greater-than or equal operator. Returns true if the first argument is greater than or equal to the second argument.
( ) [if !(IE 7)] Subexpression operators. Used in conjunction with Boolean operators to create more complex expressions.
& [if (gt IE 5)&(lt IE 7)] The AND operator. Returns true if all subexpressions evaluate to true
| [if (IE 6)|(IE 7)] The OR operator. Returns true if any of the subexpressions evaluates to true.

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<!--[if gte IE 7]> <SCRIPT LANGUAGE="javascript"> alert("Congratulations! You are running Internet Explorer 7 or a later version of Internet Explorer."); </SCRIPT> <P>Thank you for closing the message box.</P> <![endif]-->

 

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<!--[if IE]><p>You are using Internet Explorer.</p><![endif]--> <![if !IE]><p>You are not using Internet Explorer.</p><![endif]>   <!--[if IE 7]><p>Welcome to Internet Explorer 7!</p><![endif]--> <!--[if !(IE 7)]><p>You are not using version 7.</p><![endif]-->   <!--[if gte IE 7]><p>You are using IE 7 or greater.</p><![endif]--> <!--[if (IE 5)]><p>You are using IE 5 (any version).</p><![endif]--> <!--[if (gte IE 5.5)&(lt IE 7)]><p>You are using IE 5.5 or IE 6.</p><![endif]--> <!--[if lt IE 5.5]><p>Please upgrade your version of Internet Explorer.</p><![endif]-->   <!--[if true]>You are using an <em>uplevel</em> browser.<![endif]--> <![if false]>You are using a <em>downlevel</em> browser.<![endif]>   <!--[if true]><![if IE 7]><p>This nested comment is displayed in IE 7.</p><![endif]><![endif]-->