What Does HTML5 Include?

By 2007, all the excitement was in the WHATWG camp. After some painful reflection, the W3C decided to disband the group that was working on XHTML 2 and work on formalizing the HTML5 standard instead. At this point, the original HTML5 was broken into more manageable pieces, and many of the features that had originally been called HTML5 became separate standards.

There’s no such thing as a browser that “supports” HTML5. Instead, every browser supports a gradually expanding subset of HTML5 related features. This approach is both good and bad. It’s good because the browsers can quickly implement mature parts of the HTML5 standard while other features continue to evolve. It’s bad because it forces web page writers to worry about checking whether a browser supports each feature they want to use. (You’ll learn about the painful and not-so-painful techniques to do so in this book.)
Here are the major feature categories that fall under the umbrella of HTML5:

• Core HTML5. This part of HTML5 makes up the official W3C’s version of the specification. It includes the new semantic elements , new and enhanced web form widgets , audio and video support , and the canvas for drawing with JavaScript . This category includes most of the features that have the best browser support.
• Features that were once HTML5. These are the features that sprang from the original HTML5 specification, as prepared by the WHATWG. Most of these are specifications for features that require JavaScript and support rich web applications. The most significant include local data storage , offline applications, and messaging, but you’ll learn about several more in this book.
• Features that are sometimes called HTML5. These are next-generation features that are often lumped together with HTML5, even though they weren’t ever a part of the HTML5 standard. This category includes CSS3 and geolocation.

Oddly enough, it’s not just clueless managers and technology writers causing the standards confusion. Even the W3C is blurring the boundaries between the “real” HTML5 (according to the standard) and the “marketing” version (which includes everything new and the kitchen sink). For example, the official W3C logo website (www.w3.org/html/logo) encourages you to generate HTML5 logos that promote CSS3 and SVG two standards that were under development well before HTML5 appeared.