HTML5 (HyperText Markup Language) is a standard (currently a working draft) for the semantic markeup of web content. Development has been ongoing for some time, and while parts of HTML5 are still work in progress it is already being used as living standard in the development of new web sites.
HTML5 has brought many new content elements and properties that underpin the development of the World Wide Web towards an application platform and carrier for media content:
- There are new elements ofr the semantic mark-up of web content such as main content (
main), arcticles or content sections (
article), navigation sections (
nav) header areas (
header), footer areas (
footer) or asides (
- The new elements
audiosimplify the inclusion of multimedia content on web pages
captionimprove the semantic inclusion of illustrations or diagrams on web pages
- For the form element
inputnew types exist (e.g..
number), smplifying error handling when users make input errors
- WAI-ARIA is now a part of HTML5 - ARIA roles and properties will validate in a HTML5 validator
- It is now possible to save session data such as user input locally, in users' browser
A good resource about HTML5 and questions around implementation is HTM5Doctor.
HTML5 and accessibility
Elements and attributes that were taken over from HTML 4.01 are usually still accessible. A few attributes that were intended to improve accessibilty but were rarely used (and when used, often used incorrectly) may be scrapped in HTML5, for example, the
summary attribute in tables and the
longdesc-attribut for images.
The accessibility of neuen HTML5 elements and attributes largely depends on the degree of support by operating systems, browsers and assistive technology and is bound to improve significantly as HTML5 gains ground and software is updated. The web site HTML5Accessibility offers a good first overview of current support across platforms.
Developers intent on ensuring the accessibility of HTML5 elements and attributes can at times resort to WAI-ARIA to add semantics that correspond to the native HTML5 semantics but are currently better supported. See HTML5 accessibility - a work in progress: Example solutions.
HTML5 in two versions?
HTML5 is being prepared by two different working groups.
- There is the WHATWG (Web Hypertext Application Technology Working Group), wcih develops HTML5 als Living Standard and is influenced, if not guided, by the interests of browser manufacturers. What elements and properties are given permanent residence in the HTML5 Living Standard depends on actual implementations in at least two different browsers.
- At the same time, the HTML Working Group of W3C is working to produce a fixed, 'time slice' HTML5 standard following the usual consensual W3C process. It has published a HTML5 Candidate Recommendation in August 2013 and now works on version HTML5.1. This version is frequently updated (in so-called nightlies) to include most additions of the HTML5 Living Standard of WHATWG. In additon it adds its own proposals that are backed by user research, for example, the
Much of the development of HTML5 happens in extension modules. An example is the
canvas element and competing variants of a new image element or attribute to cater for varying image sizes depending on the device (
picture element versus
srcset attribute). Once new elements or attricbures are sufficiently supported in browser implementations they will moved into the HTML5 core spec.