How to spy passwords for asterisks on the page

Immediately forgive me if this has already been discussed.
Sometimes it is very necessary to remember the password, but it is a bastard is saved and only stars are visible. My favorite Firefox has a built-in password view function and it is located in:
Tools -> Settings -> Security -> Saved Passwords
Press the button to display passwords and voila - all codes are in full view.

But today I found a simpler cross-browser way:

Just go to the page where we see the Login and the hidden password, and then enter the following into the address bar:
')
javascript:(function(){var s,F,j,f,i; s = ""; F = document.forms; for(j=0; j<F.length; ++j) { f = F[j]; for (i=0; i<f.length; ++i) { if (f[i].type.toLowerCase() == "password") s += f[i].value + "\n"; } } if (s) alert("Passwords in forms on this page:\n\n" + s); else alert("There are no passwords in forms on this page.");})();

Actually, I just added it to the bookmarks and now with one click of a button I can spy the password if it is lost or I forgot it.