Here you can find different online proxy checkers. For use thats you don't need download or setup any software, don't need to change any settings of your browser. Just open web page, enter your proxy name(s) and port(s) and check it!
ProxyChecker online checker - Anonymously checks HTTP proxies for support and proper functioning. It doesn't work.
AtomInterSoft Online Proxy Checker - checks only HTTP proxies. Can check for anonymity, shows detailed information about proxy.