Firefox includes a built-in PDF viewer to display PDF files inside the browser window. This article explains how to use the built-in PDF viewer, how to fix the common issues you might encounter, and how to use another PDF viewer.

Download: Click the Download button to save the PDF file to your computer or to open it with a PDF reader program. Copy current view: Right-click Hold down the control key while you click the current. Instead, it will go straight to the download manager and begin to download. Second; whenever a PDF file is downloaded, clicking it in the downloads bar will open the file in your default desktop PDF reader. Disable PDF Viewer in Firefox. To disable the PDF viewer in Firefox, type the following in the URL bar, and accept the warning from the page.

Table of Contents

• 1Firefox’s built-in PDF Viewer

Firefox includes a built-in PDF viewer that allows you to view almost all PDF files found on the web without an external application (exceptions to this are PDF files with a MIME type incorrectly set). This built-in PDF viewer is enabled by default. When you click on a link to a PDF file or open it from the Firefox Downloads panel, it will be rendered with the built-in pdf viewer.

Fill out forms in PDF Viewer

Some PDFs files have interactive fields to fill in data (such as on forms). Using Firefox's built-in PDF viewer you can fill out fields such as text, check boxes and radio buttons. After entering data into these fields you can download the file to have the filled out version saved to your computer.

PDF Viewer toolbar functions

• View document thumbnails or outline: The slider button on the far left will open a sidebar with thumbnails of the document's pages. Some documents will also have an outline view available. These make it easy to navigate through a long document.

• Page up and down or skip directly to a page: You can use the up and down arrows to page through a document or enter the number of the page you want to go to.

• Change the size of the document: Use the + and - buttons to zoom in and out or choose a zoom setting from the dropdown menu.

• Fullscreen or Presentation mode: Click the fullscreen button to allow the PDF file to take over your entire screen. Press ESC to exit fullscreen mode.

• Print: Click the Printer button to open the print setup dialog.

• Download: Click the Download button to save the PDF file to your computer or to open it with a PDF reader program.

• Copy current view:Right-clickHold down the control key while you click the current view button to open the current view in another tab or window.

PDF Viewer keyboard shortcuts

Troubleshoot problems with the PDF viewer

• With certain types of PDF files, the PDF Viewer may have problems displaying fonts, colors or the whole document. If some PDF files don't render well or are blank, click the download button on the right side of the document header to open it with the default PDF viewer application on your computer.

• If you can't open any PDF files with the built-in PDF viewer, a Firefox extension could be the cause. You can disable all of your extensions, to see if one of them was the problem. For details, see Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems.

You can also use a different third party PDF viewer instead of Firefox’s built-in PDF viewer. To change from using the built-in PDF viewer to another PDF viewer:

1. Click the menu button and select ..
2. In the General panel, go down to the Applications section.
3. Find Portable Document Format (PDF) in the list and click on the entry to select it.
4. Click on the arrow under the Action column for the above entry and select the PDF viewer you wish to use from the drop-down menu.

If you want Firefox to always ask you what to do with PDF files, follow the above steps to change the action for the Portable Document Format (PDF) entry, except select Always ask from the drop-down menu. The next time you click on a link to download a PDF file, Firefox will show you a prompt asking what to do with the file. You can then choose to open it with Firefox's built-in PDF viewer, open it with a different PDF application, or you can choose to save the file.

For more information, see Change what Firefox does when you click on or download a file.

You can choose to have Firefox’s built-in PDF viewer as the default for viewing PDFs in the browser but open downloaded PDF files with a third party tool. To open a PDF file you downloaded in Firefox, using a third party viewer:

Disable Downloads Windows 10

1. Open the Downloads panel by clicking the download icon next to the address bar.
2. Right-click on the file folder icon of the PDF file and select Open Containing Folder.Hold down the control key while you click (two finger click) the magnifying glass icon of the PDF file and select Show in Finder.
3. Then in the Downloads folder, right-clickControl-click on the file and select Open with and choose your favorite PDF viewer.

When Acrobat is not set as the default PDF handler and it is launched, a dialog prompts whether to make Adobe Acrobat the default PDF application.

Disable Pdf Download From Browser

You can select the Do not show this message again check box to suppress the message.
Once the check box is selected, a registry key corresponding to it is preferred and is created at the registry path as follows:
[HKEY_CURRENT_USERSoftwareAdobe(product name)(version)AVAlertcCheckBox]
DWORD: iAppDoNotTakePDFOwnershipAtLaunch which is set to value 1
**If AVAlert or cCheckbox do not exist by default, then select the Do not show this message again check boxon the dialog box and then recheck.
For Windows 10, the name of the DWORD is iAppDoNotTakePDFOwnershipAtLaunchWin10
Possible values of this registry key are:
1: Do not show this message again
0: Show this message every time Acrobat is launched until it is set as the default PDF handler.
You can create the key manually or use it using deployment to suppress the message.