PDF.js vs PrizmDoc HTML5 Document Viewer


PrizmDoc PDF.JS Comparison

PDF.js is free, but underperforms PrizmDoc in 5 different feature/performance areas

The ability to display files to users directly in the web browser is a common need for web and applications. Image files, word documents, and spreadsheets are common examples of information that users need to be able to view as they go.

PDFs are also very popular file types, and the need to embed them in websites and apps has spawned a market full of products available to developers. Accusoft's PrizmDoc is an established tool for the comprehensive handling of PDFs and many other file types, but several open source options have emerged over the years as well, including PDF.js.

Created by Mozilla developers for the popular Firefox browser, PDF.js found prominence quickly, not only because it's free but because it uses HTML5 and is written in JavaScript, with simple code integrations. Consequently, it rarely has compatibility issues with various operating systems and browsers, and end users are rarely aware of its presence at all while viewing content.

But while PDF.js has found a comfortable niche among developers looking for a simple - and free – solution to displaying just one particular file type, many apps require a more versatile viewer, one that can handle a host of different files and facilitate searching and editing functions at a minimum.

Realizing that these needs are always expanding, our engineers put together a whitepaper detailing a few key characteristics to look for in a document viewer, streamlining the process of gathering and processing information with a single resource.

With that list in mind, here are some key functional areas which illustrate PrizmDoc's performance advantages over PDF.js:

File format support

File Types

This is an area in which PrizmDoc far outpaces open source options, as evidenced by the screen grab above in the document viewing demo page. PDFs are a major priority, of course, but both vector- and raster-based image files are also handled with ease, as well as Word documents and Excel spreadsheets. Even DICOM files, widely used in the medical world in areas such as radiology and magnetic resonance imaging (MRI), are supported in PrizmDoc, as are DWG files for AutoCAD applications. PDF.js, as the name suggests, only handles PDFs. See the Tech Specs page for a full list of the supported file formats.



PrizmDoc has this functionality built into its basic toolbar (click here for standard demo). It lists all the instances of the search argument it finds in the far left column (as shown above in a simple search for the word 'file'), with hotlinks to each occurrence. PDF.js offers a basic "find" function, but does not provide full-fledged search features such as the results list for quick reference, which can be cumbersome in the case of large files. This isn't a major problem for many users, of course, but legal and real estate applications, for instance, could be slowed down greatly.



This is the ability to comment or markup presented data, such as underlining or highlighting passages, jotting notes on the side or adding shapes such as circles to emphasize key elements. PDF.js enables this through an add-on utility, but PrizmDoc offers annotations out of the box, with more refined annotation tools than PDF.js. PrizmDoc's ease in handling multiple file types is important here as well. It offers the ability to point out key numbers in a spreadsheet or an important part of an image, for instance, and do so with an expanded palette of shapes, colors and images.


The capacity to conceal sensitive information, particularly in financial and legal documents, is crucial and often required by law. PrizmDoc allows users to cover specific fields on forms or other documents whenever desired (such as email address and phone number above) and as often as needed in a structured approach. Redaction can be done automatically based on a set of rules, or manually. PDF.js touts its ability to redact specific pages in documents, but lacks the functionality to redact individual words, phrases, numbers and fields.



This allows an organization (an employer, for instance) to confirm that the end user has reviewed and understands forms required to move forward in a process, such as employee onboarding. PDF.js does not have this very useful functionality.

There are other areas in which PrizmDoc leads the way in the document viewer industry, with especially glaring advantages over open source options:

Product Support

Product Support

Accusoft's developer support team is always at the ready to assist with any problems or questions users might have with PrizmDoc. We even offer a Service Level Agreement with one-hour support response times guaranteed, if needed.

Responsiveness to customer needs

Responsive to Customer Needs

An investment in PrizmDoc doesn't create access to a static product, but rather a development solution that continually improves with emerging technologies. PrizmDoc is frequently updated and enhanced, for example version v. 13.0 in the fall of 2017 added new features for document comparison and to improve CAD and vector image viewing.

There are times when free (or very cheap) options will suffice in solving a problem. But when choosing a document viewer, depth of program functionality is key since a robust selection of features can have a significant impact on meeting business goals.

Product support, for instance, speeds up implementation, reduces the likelihood of bugs and makes future compatibility less likely to be an issue. Other attributes of PrimzDoc, such as the ability to display a wealth of different file types, can significantly improve the efficiency of numerous departments who have varying needs and use different sources of information.

We encourage you to view our PrizmDoc demos and sample code to see what PrizmDoc offers and how it could be integrated to provide the document viewer features you need. And contact us with any questions you may have about its power and functionality. Review our customer case studies to discover what PrizmDoc - and Accusoft itself - have to offer you.

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