You can add some extensions and add-ons in your browser to steal passwords easily. These are local keyloggers which capture every strokes of keyboards. Very useful for monitoring what others do on your laptop and also useful for stealing password of anyone who login in your computer.
Add-Ons for Firefox
Keylogger 1.5
By Lipo-technologies
This addon logs down every single key press performed on the computer while surfing the browser.
To install it , press shift+ctrl+A which opens the add-ons. Search by its name and install. Pretty easy 
.
After installing press alt+l, enter the new password and its done.
You can press alt+l and see the keystrokes recorded by it.
Xenotic Keylog X 1.0
By Ajin Abraham
This addon is similar to Keylogger 1.5. After installing press alt+X (hotkey for opening the keylogger), enter the new password and its done.
Extension for Chrome 
Gumshoe
Gumshoe is a Chromium extension for discreet password logging. It monitors the submission of all forms with a password field and stores any unique login details in a local database.
Installation:
The Chrome Web Store isn’t likely to host our totally innocent extension, so it’s Plan B
Go to github.com then go to explore and search gumshoe, download gumshoe.crx. Click “Continue” on bottom-left prompt Click “Install” on popup prompt Getting Started Once installed, typing gselog anywhere
should reveal the log management page. From here, you can search for records, delete those records, and change gselog to something more creative.
Laptoplookout
Download the extension for chrome. Click the icon, and make an account in the pop up. Confirm your email address.
If your computer gets stolen: Sign in to www.laptoplookout.com report your computer stolen. Watch the tracking data start rolling in almost immediately
PS: This article is originally published in HACKITUDE as Extension for Hacking by M@d H4xor.
john
September 20, 2012
Hi
Re: gumshoe. typing gselog is not working. It brings up a simple google search result.
John
hackitudemagazine
November 21, 2012
go to settings of gumshoe and change the default key
Dut
November 29, 2012
Yeah, Uh. Where are the settings for gumshoe?
hackitudemagazine
November 30, 2012
well for that you have to open google.com search gselog then you will get the property where you can change default passkey
hackitudemagazine
November 30, 2012
you have to open google.com first. Do not write gselog in Omnibar(address bar) of google chrome. Open google.com then search gselog
buche
February 2, 2013
FF extensions show up in the Tools/Addons installed page! Any discreet loggers you know of? Cheers!
buche
February 2, 2013
Please don’t judge people, its for my kids safety of course.
KlOgin
May 16, 2013
I have tried typing gselog in google search and all. nothing coming up for it but the github site
hackitudemagazine
May 18, 2013
you have to install the plugin from github.
btw its a old trick … so there are chances that it will not work