Browser support for box-shadow
Basic box shadow Show archive.org snapshot support is available in all browsers today, but you need to check to which extend they are supported. Implementations differ:
- Are multiple box shadows (separated by comma) possible?
 - Are inset shadows possible?
 - Can the spread radius be defined?
 - Can you use it without vendor prefix?
 
A good compatibility chart can be found here Show archive.org snapshot . The gist is that, except for IE and some Safaris, you can use all features today without vendor prefixes.
Support of all features is guaranteed in:
- Firefox 4.0
 - Chrome 10.0
 - Internet Explorer 9.0
 - Opera 10.5
 - Safari 5.1