1. The Boom of Web APPs
A Web APP is a computer program that utilizes Web browsers to perform tasks either online (over the internet) or offline. Before 2013, virtually all Web APPs require internet connection because most browsers did not have a full support for offline applications yet. Today, the ubiquitous support of Web browsers for offline APPs could make the traditional ebook readers (viewers) obsolete.
All APPs can be divided into three categories: Web APP, native APP and hybrid APP. The native APP does not rely on Web browsers. It is built from the ground up. As such, its development is the most demanding. This disadvantage was not serious in the old days when Windows was the dominate operating system. But now there are many competitors: iOS, Android, Mac, Chrome OS, Firefox OS, etc. For each operating system, you need entirely different codes. Even worse, after an operating system is updated to a new version, you have to modify your codes. Therefore, native APPs are very labor-intensive and cost-ineffective.
Hybrid APP has been commonly used in mobile devices. It depends on the interface provided by the operating system, which makes the development a lot easier. However, the hybrid APP is not cross-platform because each operating system provides its own interface. In contrast, the Web APP relies on the interface provided by the Web browser. These interfaces are specified by the HTML5 standards. Therefore, a Web APP should work on ALL browsers that support HTML5. In the past few years, more and more HTML5 features have been implemented in modern browsers on both laptops and mobile devices.
Despite the tremendous advantage of Web APPs, almost all ebook readers that exist today belong to hybrid APP. Between 2012 and 2016, Kobo and Barnes and Noble attempted to develop a Web APP for reading the popular EPUB format, but failed (reference). Amazon has also developed the Kindle Cloud Reader (close, but not a full-fledged Web APP) to read their proprietary ebook format. In July 2020, the Kindle Cloud Reader has removed the offline reading function. It looks like it is on the verge of being discontinued (reference). Why don't developers of ebook readers use full Web APPs for offline reading? A major reason could lie in the ebook format (see next chapter).