How to do it...

1. To install Firefox, open a browser and enter the following URL:
   https://www.mozilla.org/firefox.
2. Click the button that says Download to download the installer.
3. After the installer has finished downloading, double click the installer and follow the onscreen instructions.
4. To configure Firefox, open the Firefox browser and enter the following URL: 
   about:config.
5. The menu will allow you to enable advanced and experimental features. If you see a warning, click the button that says I accept the risk!
6. Find the dom.moduleScripts.enabled setting, and double-click it to set the value to true, as shown in following screenshot: