Firebug is a popular web development tool that allows you to inspect and debug HTML, CSS, and JavaScript code on a web page. It is available as an add-on for the Firefox web browser.
To install Firebug in Firefox 3, follow these steps:
Open the Firefox web browser.
In the address bar, type about:addons and press Enter. This will open the Add-ons Manager.
In the Add-ons Manager, click the "Extensions" tab.
In the search box, type "firebug" and press Enter.
Click the "Add to Firefox" button next to the "Firebug" add-on.
Click the "Install" button in the installation prompt.
Wait for the installation to complete.
Click the "Restart Now" button to restart Firefox and complete the installation.
After installing Firebug, you can access it by clicking the "Firebug" button in the Firefox toolbar.