This works in Internet Explorer, Firefox, Netscape and Opera browsers
Go to a page that has a password hidden by ***’s then just paste this simple script below into your browser bar and it will pop up a messagebox showing your password.

This script replaces the ****’s with the plaintext password , works in Firefox only

Also quick access to Firefox’s password manager instead of going through the menus
Paste this in your browser: chrome://passwordmgr/content/passwordManager.xul