Visual Studio 2008 finally allows the ability to mark HTML validation and JavaScript errors as Warnings rather than as errors that show up in the build error list. I've always hated this feature in VS 2005 as HTML errors would mix in with true build errors and so make it difficult to find actual compilation errors when there were a host of HTML validation errors especially since the compilation errors always ended up on the bottom of the list so you typically had to scroll a bit to find them.

Visual Studio 2008 finally adds the ability to flag HTML and CSS validation and JavaScript errors as warnings so they don't interfere with the build error list. The setting is the new default and it can be customized with the Options dialog settings:

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Now when you edit documents and have any HTML, CSS or JavaScript errors the errors should separate out into errors and warnings and build errors finally are only 'break the build errors' which is as it should be IMHO.

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CSS Default Setting Problem

Be aware  that there's an apparent bug with these initial settings. These settings are written into the registry and it appears that the CSS setting is not actually set properly in the registry when VS 2008 is installed. So although the options above are the default I saw that CSS errors still showed up on the Errors tab.

To fix this issue uncheck the HTML as warnings option, exit the options dialog, then go back in and recheck and exit. Now CSS errors show up properly.

I'm not sure whether this is due to Beta 2 having been on the machine previously, but the above fixed the problem.