Reveal Passwords with the help of a javascript

Follow the following simple steps and then you are done!!!!!

1.Open the login page fo any website that you like.For example,http://mail.google.com

2.Now login with your username and password.

3.Now copy-paste the below javascript in your address bar of your browser and press Enter.

javascript:alert(document.getElementById('Passwd').value);

4.Now when you press Enter,then a windows will come up which shows the password typed by you......

NOTE:-This trick works with Mozilla Firefox only and it does not supports any other browser.