To enable or disable the built-in PDF viewer in Mozilla Firefox, follow these steps:
- Open Mozilla Firefox and click on the three horizontal lines in the top-right corner to access the menu.
- From the dropdown menu, select "Options" (or "Preferences" on macOS).
- In the Options/Preferences tab, click on "General" in the left sidebar.
- Scroll down to the "Applications" section.
- In the search bar within the Applications section, type "PDF". This will filter the list and display the options related to PDF handling.
- Locate "Portable Document Format (PDF)" in the list and click on it to select it.
- On the right-hand side, you will see a dropdown menu labeled "Action". Click on it and select the desired action:
- To enable the built-in PDF viewer, select "Preview in Firefox" or "Use Firefox".
- To disable the built-in PDF viewer, choose "Always ask" or "Use other..." and select another PDF viewer installed on your computer.
Note: If you choose "Use other..." and select an external PDF viewer, Firefox will prompt you to download the file instead of opening it in the browser.
- Close the Options/Preferences tab.
After following these steps, the built-in PDF viewer in Mozilla Firefox will be enabled or disabled depending on the option you selected.