The Mozilla (News – Alert) Corporation today released Firefox 19 for Windows, Mac and Linux desktop users, bringing a number of bug fixes to the browser. However, the new feature that’s getting the most attention is the inclusion of a built-in PDF viewer based on HTML5.

While this feature was previously available in Firefox betas, this is its first time being included in a stable release. The result of a research project called PDF.js, this new PDF viewer leverages standard HTML5 APIs, enabling Firefox to quickly render standard PDF files without the need for an additional plug-in. As such, Firefox no longer requires Adobe’s (News – Alert) Reader PDF plug-in, or even alternatives such as Foxit Reader or Sumatra PDF.

This may come as a relief to many users as loading up PDFs with the Adobe Reader plug-in could often be slow. Since Firefox now uses HTML5, it will likely lead to a much quicker, smoother experience. That said, some have reported that font rendering seems to be a bit off, resulting in somewhat blurry text.

The rest of the fixes and additions present in Firefox 19 are largely geared more toward developers and as such won’t affect the average user much. These include start up performance improvements, support for pausing on exceptions and hiding non-enumerable properties in the debugger, a Remote Web Console for connecting Firefox on Android or Firefox OS and a number of CSS (News – Alert) (cascading style sheet) fixes.

In other recent Mozilla news, the company launched two developer preview smartphones last month for its Firefox OS project, which aims to provide an alternative to Android (News – Alert) on low-cost mobile devices. The phones, called the Keon and the Peak, were made with Spanish smartphone manufacturer Geeksphone.

In December, Mozilla demonstrated WebRTC integration in Firefox at the WebRTC Conference and Expo, including not only real time video conferencing, but also file transfer capabilities.