Here is my code, I got it from an AJAX sample:

I am getting the following errors:

Error 1 Validation (CSS 2.1): ‘opacity’ is not a known CSS property name. C:\Documents and Settings\agordon\My Documents\Visual Studio 2008\WebSites\WebSite3\StyleSheet.css 402 2 C. \WebSite3\ Error 2 Validation (CSS 2.1): ‘filter’ is not a known CSS property name. C:\Documents and Settings\agordon\My Documents\Visual Studio 2008\WebSites\WebSite3\StyleSheet.css 403 2 C. \WebSite3\ Error 3 Validation (CSS 2.1): ‘filter’ is not a known CSS property name. C:\Documents and Settings\agordon\My Documents\Visual Studio 2008\WebSites\WebSite3\StyleSheet.css 427 2 C. \WebSite3\ Error 4 Validation (CSS 2.1): ‘opacity’ is not a known CSS property name. C:\Documents and Settings\agordon\My Documents\Visual Studio 2008\WebSites\WebSite3\StyleSheet.css 428 2 C. \WebSite3\ Error 5 Validation (CSS 2.1): ‘lemonchiffon’ is not a valid value for the ‘background-color’ property. C:\Documents and Settings\agordon\My Documents\Visual Studio 2008\WebSites\WebSite3\StyleSheet.css 738 23 C. \WebSite3\ Error 6 Validation (CSS 2.1): ‘lemonchiffon’ is not a valid value for the ‘background-color’ property. C:\Documents and Settings\agordon\My Documents\Visual Studio 2008\WebSites\WebSite3\StyleSheet.css 759 23 C. \WebSite3\

Does anyone know what I am doing wrong?

asked Aug 30 ’11 at 17:00

Validation errors are all fine, because they are using the proper CSS 2.1 Documentation and your trying to validate CSS3 properties in a CSS 2.1 context.

What you probably want is to build your application by-passing the CSS Errors, no matter what they are. for that you can transform this “errors” into warnings using Visual Studio Options:

in The Visual Studio menu click on:

Tools > Options. and drill down Text Editor > CSS > Miscellaneous

and just make the CSS Errors to be treated as warnings

I realize that this response is a little late, but someone else may find this information useful.

To make the filter tag warning go away in VS2010 (as opposed to just ignoring it), close VS2010 and edit the following file: C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\Packages\1033\schemas\CSS\css30.xml

You need to change the filter property from enum to composite.

Around line 387, you should find the following text: cssmd:property-def _locID=”filter” _locAttrData=”description,syntax” type=”enum”.

Change it to: cssmd:property-def _locID=”filter” _locAttrData=”description,syntax” type=”composite”.

Then restart VS2010.