Steps to install Firebug

Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page...
For QA, this is a helpful tool to indicate ID, Name or xpath of components on the webpage.
Steps to install:
1. Launch Firefox and navigate to https://addons.mozilla.org/en-US/firefox/addon/firebug/
2. Click on button "Add to Firefox"

3. Click on "install" button from popup dialog

4. When the installation finish, you will see a dialog appear

5. Tool > Web Developer > Firebug >  Open Firebug of press F12 to open Firebug

6. Firebug window is shown as below: