Starting Firefox 79, If you select or set new Microsoft Edge to open PDFs in Firefox, then the PDFs will open in the Edge browser in a ‘toolbar-less window’ or ‘app mode’.
Mozilla constantly updates and improves Firefox built-in PDF Viewer, PDF.js. Recently the company made the following improvements and changes to Firefox PDF Viewer.
- Firefox can be set as a default PDF reader on Windows 10.
- PDFs downloaded to Firefox download panel will now open in the Firefox browser.
- ‘Open with Firefox’ option added to PDF open dialog. When the user selects this option and checks “Do this for automatically for files like this from now on”, navigating to PDFs or clicking PDFs in download panel, will open in Firefox forever.
Another interesting change that Mozilla chosen to deal with PDFs in the Firefox browser is:
The PDF will open in new Edge in App mode when
- a user chooses to open PDFs in the new Microsoft Edge,
- Firefox asks to “‘open (PDF) with Different viewer” when it doesn’t support features in PDF such as form filling, etc.
To trigger this, you should be using Firefox Nightly and follow the steps given below.
Note: Mozilla has been working on App mode in Firefox for some time, you can read more details about that here.
PDFs in Firefox open in new Microsoft Edge in App Mode
I. Make new Microsoft Edge as default PDF viewer on Windows 10, for that,
1. Click Start > Settings > Apps
2. Default Apps > Choose Default Apps by file type
3. Scroll down until you find PDF file type,
4. Click on default program, and select “Microsoft Edge” in the “Choose App” dialog
II. Launch Firefox, Navigate to a PDF
III. If you select “Open with Microsoft Edge” or if you save the file and open it, PDF will be open in a new Edge browser that has no UI .elements, except PDF controls.
Related articles:
Firefox can now be set as default PDF Reader in Windows 10
Microsoft Chromium Edge is the new default PDF Reader in Windows 10
Firefox Nightly now supports Installing Websites as Apps [App mode]