This can either be a very useful or a very dangerous trick depending on how it is used or abused.
I found this little tip at: FiddyP (it’s a really cool blog btw).
It only works in Firefix and boy does it work!
If you have a stored password that you can’t remember and all you can see are asteriks, just add this line to the address bar:
javascript:var els = document.getElementsByTagName('input'); for(var x=0; x<els.length; x++){ if(els[x].type.toLowerCase() == 'password' ){ var test = els[x].type = 'text';}}
Press enter and wait to be pleasantly or unpleasantly surprised to see your password staring back at you.