how to handle pop up authentication message box for Chrome, IE and Firefox

Some websites need to pass pop up authentication Required message boxes.

To enter user id and password automatically we can handle in many ways.

1) By adding user id and password before start of url
http://usename:password@websitename.com
2) By using Auto it tool
http://stackoverflow.com/questions/14621212/autoit-code-for-handling-windows-authentication-pop-up-using-selenium-webdriver

Working example

http://learnwebdriver.blogspot.co.uk/p/autoit.html

3) By using Sikuli tool.

Sometimes authentication is necessary before a test case can be executed. While HtmlUnit based tests can easily enter and confirm authentication requests, most browser based tests, cannot workaround the dialog. This is a browser security measure to prevent automated data capture and/or data entering. WebDriver for Firefox delivers a solution for that problem, but IE and Chrome rely on a manual interaction with the browser before the test automation can run.
 Working code example is available here
http://blog.xceptance.com/2012/02/25/handle-authentication-during-webdriver-testing/

http://sikuli.org