The W3C (World Wide Web Consortium, w3.org) is responsible for defining standards around HTML. One of the most prominent current developments is HTML 5.
In addition, HTML is defined by the WHATWG (Web Hypertext Application Technology Working Group), an organization not associated with W3C. The WHATWG was created by Apple, Opera and Mozilla after the companies felt that the W3C's HTML Working Group (HTMLWG) didn't move fast enough.
These days, the HTMLWG and the WHATWG are working together, but they are taking a different approach to the future development of HTML. The WHATWG is defining HTML as a constantly developing, living standard. The HTMLWG is taking various snapshots of the WHATWG standard, and defining them as an HTML version.
Here are some of the more recent notable additions to HTML, which are usually kept under the umbrella of HTML 5:
- Access to hardware sensors: Most browsers already support GPS geolocation, or access to other geolocation APIs of the hosts (e.g. via WiFi). But sensors like accelerometers commonly found in mobile devices are supported as well. Recently, support for the access to cameras and microphones emerged but support is still spotty.
- Extended storage options: Traditionally, web applications had to store data in cookies. Cookies are rather limited in size, and wouldn't scale to a larger size as they are sent with each request. With HTML 5, web applications can store up to 20 MB on the browser, and if that's not enough, they can ask the user for permission to store more data.
- Video/Audio codecs: the video and audio tags allow for the playback of audio without the help of plugins like Flash or Java. However, not all browsers support the same codecs.
There are many more features that are part of the most recent HTML specs, and browsers are starting to implement them. Which features you will find depends on the browser you are using.
Johannes B. Ullrich, Ph.D.
SANS Technology Institute
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