CSS Browser Selector + is a very small JavaScript which empowers CSS selectors. Selector + CSS Browser is good help to develop a cross-browser site without using Hacks.

With it you can develop responsive sites for browsers that do not support Media Queries module (CSS3) and without using hacks (not character validated by W3C).

The script adds classes that do a deep scan on the client browser, opening up a range of opportunities for customization, thus being able to extend these capabilities to even newer browsers.