For a number of years there have been several plugins for viewing PDF’s within Firefox. Many of these plugins come with proprietary closed source code that could potentially expose users to security vulnerabilities. PDF viewing plugins also come with extra code to do many things that Firefox already does well with no proprietary code, such as drawing images and text. These problems, and the desire to push the boundaries of the HTML5 platform, led Andreas Gal and Chris Jones to start a research project they named PDF.js. The project quickly picked up steam within Mozilla Labs, where it grew into a full-fledged PDF viewer.