The Firefox browser allows you to temporarily enter and exit full-screen mode by pressing the "F11" key. This is a useful feature because it allows you to view more of the Web page on the screen by removing the tool bars and menus. However, there some instances where it is beneficial to always keep the browser in full-screen mode, such as when you are using it in a public kiosk. You need to install an applicable Firefox add-on that can enable this feature in the browser.
Launch Firefox, then go to the Firefox add-ons Web page.
Type "Full Screen" in the Search bar at the upper-right corner of the screen. Press "Enter" on your keyboard. A list of add-ons that offer full-screen capability for Firefox is displayed. Some examples are: Full Fullscreen, Real Fullscreen and Kioskfox.
Click on the name of an add-on from the list you are interested in. Scroll down the page to view the details of the add-on. Review as many full-screen add-ons as you need to determine the best one for you.
Click the "Add to Firefox" button next to the full-screen add-on that you want. The add-on is automatically downloaded to Firefox.
Click the downloaded "Add-on" in the pop-up software installation window, then click the "Install" button.
Click "Restart Now" to restart Firefox when prompted. The add-on is automatically activated. Typically, to enter the permanent full-screen mode using a full-screen add-on, press the "F11" key. Once the full-screen mode is activated, pressing "F11" is the only way to deactivate it. Moving the mouse or pressing a different key on the keyboard will not cause the menus or toolbars to display, unlike the Firefox built-in full-screen utility.
To view the available options for a full-screen add-on, click the "Firefox" button on the top-left corner of the browser's window, and then select "Add-ons." Click the "Options" button to the right of the full-screen add-on from the list.