Mozilla published the latest stable version of Firefox 19 for Windows, Mac, Linux and Android, and a built-in PDF viewer is among the top features.

The Portable Document Format, a.k.a. PDF, is one of the most common document types both on the Internet and on personal devices. It can distribute all sorts of formatted documents, from brochures to manuals and other things, and it definitely shines in terms of new features on Mozilla's otherwise short update list.

Firefox is one of the most popular browsers currently available, partly due to its compatibility with OS X, Windows and Linux. As ubiquitous as the PDF format is, until this version of Firefox no browser offered a built-in PDF reader. This means the users had to either install a browser plug-in such as Adobe Reader or download the PDF and open it in a managing program. This can be a source of security vulnerabilities, as well as a slight inconvenience.

Now, Mozilla includes a native PDF viewer in the latest version of Firefox, aiming to make it possible for users to view PDF files without needing any other programs and plug-ins. The PDF viewer is based on the Mozilla-supported HTML5 project PDF.js.

When a user opens a PDF from a Web link or from the hard drive, Firefox 19 will display it in the browser as a simple, yet efficient interface with options for zooming (either automatically or manually), viewing the PDF in full-screen presentation mode, going to specific pages by number, or scrolling through thumbnails of the loaded PDF document.

The Firefox 19 version may be short on other new features, but the built-in PDF viewer definitely brings it to the next level.

Firefox users will get the update to the latest version automatically, while users of other browsers who want to try Firefox 19 can head over to Mozilla's downloads page. This update also aims to make everything faster by not executing any code before the initial window is visible. This means that Firefox users will no longer double-click on Firefox only to see it not respond, double-click again, and again, until Firefox eventually reacts and opens 100 blank pages at once. Check out Mozilla's release notes for a full list of tweaks and bug fixes in Firefox 19.