The PDF File Viewer Explained


If you prefer to display your PDF content as PDF files, rather than as Flipbooks, you can do this by using the PDF File Viewer. Here's how it works.


What is the PDF File Viewer?

When you add PDF content to your Hub, the default way to present it is with Flipbooks. Uberflip Flipbooks are PDFs that have been converted to an image format and are displayed in an interactive viewer in a browser.

Flipbooks have several advantages over standard PDFs, but sometimes you might prefer to present your PDF content more traditionally — just as normal PDFs, in other words. In these situations, you can use the PDF File Viewer option.


When working in the Uberflip Flipbook editor, the 'Reader Version' options: HTML5 and HTML5 (SVG), are both Flipbook viewer options, while Native PDF is the PDF file viewer outlined in this article.

The PDF File Viewer is exactly what it sounds like: a viewer app that displays PDF files within a user's browser, similar to the experience you'd get in a traditional desktop PDF viewer like Adobe Reader.


The PDF File Viewer is based on Mozilla's PDF.js, an open-source, JavaScript-based PDF renderer. (If you're a Firefox user, it might look familiar: it's the same PDF viewer that's built into Firefox.)

PDF.js has several advantages:

  • It's a full-featured PDF viewer that displays PDFs directly within a browser, so visitors can consume your PDF content without needing to download the PDF file and view it in an external app;
  • It's website-hosted, so it runs automatically — visitors don't need to download or install separate PDF viewer software;
  • It's compliant with web standards, so it works in almost any browser.

As a result, if you choose to display the PDF content on your Hub just as standard PDFs, the PDF File Viewer ensures that the experience for your visitors still remains seamless and keeps them in the Hub.


PDF File Viewer Features

The PDF File Viewer has a wide range of features, comparable to desktop PDF viewers. Below is an annotated overview (click to zoom):


  1. Toggle Sidebar: Opens and closes the sidebar, which can display thumbnails of the pages in the PDF, the document outline (index), or attachments.
  2. Find in Document: Full-text word search, including highlighting functionality.
  3. Page Navigation: Navigation controls and current position in the PDF.
  4. Zoom: Zoom controls, current zoom setting, and zoom presets (e.g. Automatic Zoom, Page Fit, etc.)
  5. Presentation Mode: Switches to fullscreen view with the menu bar hidden.
  6. Open File: Opens an external PDF file (from the user's computer) in the viewer.
  7. Print: Prints the current PDF file (uses browser's printing interface).
  8. Download: Downloads the current PDF file to the user's computer.
  9. Current View: Opens the current location within the PDF in a new browser tab or window  (has to be clicked while holding down the Control key).
  10. Tools: Contains additional display and navigation options:
    • Go to First/Last Page
    • Rotate Clockwise/Anti-Clockwise
    • Toggle between Text Selection and Hand (click-and-drag navigation) tools
    • Toggle between Vertical, Horizontal and Wrapped page scrolling
    • Toggle between single-page or two-page-spread view (No Spread, Double Odd-Page Spreads, Double Even-Page Spreads)
    • View Document Properties (PDF file metadata including filename, filesize, title, author, etc.)

Feature Availability

The PDF File Viewer does not support the following Flipbook features:

  • Page Editor (including Replace Page)
  • Auto-Link Tool
  • Most Folder Options (including Page number offset, social sharing, archives)
  • Folder Widgets
  • Folder Appearance/Branding settings
  • Link styling


Accessibility Features

If you prioritize accessibility of your PDF content, the PDF File Viewer offers the following accessibility features that are not available in the Flipbook Viewer:

  • Screen reader compatibility
  • Permanent onscreen controls
  • Easy-to-use zoom functionality
  • Selectable text
  • High color contrast


Next Steps

If you'd like to use the PDF File Viewer for any of your Folders, see this article for instructions on how to enable it:

Enable the PDF File Viewer for a Folder

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