With broad compatibility, the latest in web technologies, and powerful development tools, Firefox is a great choice for both web developers and end users. Firefox OS’s promotion of HTML5 as a first class citizen opens up the walled gardens of mobile application development for web developers. It is because of this initiative that no special SDKs are required to develop for Firefox OS. This book will help you excel in the art of developing applications for Firefox OS. It sequentially covers knowledge building, skills acquisition, and practical applications. Starting with an introduction to Firefox OS, usage of WebIDE, and then the application structure, this book introduces applications of increasing complexity with each chapter. An application that measures your tapping speed, a geolocation tagging application, and a photo editing and sharing application are the three applications that will be built from scratch. You will learn about topics such as the difference between various types of Firefox OS applications, application manifest files, offline apps, and designing principles for applications. You will also learn to test and submit the applications to the marketplace and finally maintain the repository of the Firefox OS application. By the end, you will be able to develop beautifully designed, fully-fledged, and rigorously tested Firefox OS applications and also share them at the Firefox OS Marketplace.