Need to see your password to see if the one Firefox saved is correct? I run into that problem a lot – especially since I use a lot of passwords in my day to day life. One great extension for Firefox that will let you see your passwords as you enter them on a page is Show My Password.
Here is a little more about the add-on from the developer:
Once this extension is installed, just move your mouse over the password-field and the password is shown in readable letters . By default the password is shown after a 2 second delay (customizable) to prevent un-hiding by accident. You might also choose un-hiding by context menu click. More useful options available. The options screen shot above shows an example configuration which even would allow to copy/paste any scrambled password.
This most advanced unscrambling add-on shows your passwords in readable letters, while being fully customizable to fit your needs. You can pick it up from the Firefox Add-ons website.