The 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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