Ever sat there and pondered which browsers support what css styles? If so I’d like to quickly introduce http://www.caniuse.com. This is a great tool and sometimes the quickest way to find answers to your questions. But what about W3Schools; I hear you say. W3Schools does have a comprehensive list of styles, complete with examples of how to use them and a list of properties that you can use. However, what I find W3Schools fails on is a comprehensive outline of browser support.
caniuse.com provides you with a fool-proof table of browser support. It also outlines support for mobile browsers. Possibly one of the quieter features of caniuse.com is the ‘Known Issues’ tab underneath the table. So, ever tried to get rounded corners to work on a table with a background colour on the table header cells? These known issues can help you quickly debug your css.
caniuse.com isn’t limited to just css, making a great little resource for any front-enders tool kit.