VS2012 - Validation warning in CSS\9

Question

How to avoid the "Warning Message" about \9 trick in Visual Studio 2012 (C#) ?

The CSS\9 trick is related to: CSS \9 in width property

Example:

Warning 2 Validation (CSS 3.0): "\9" is not a valid value for the "outline" property

Thanks and kind regards.

Answer 1

The \9 trick is a hack. It uses deliberately invalid CSS syntax because certain IE versions have bugs that cause them to interpret it as valid when it isn't.

The fact is, it's invalid: if you've got a tool warning you about invalid code, then it's going to warn you about this.

If you want to get rid of the warnings, you're going to have to get rid of the hack and use a different method for targetting specific IE versions if you really need to do that.