So, if HTML5 doesn’t mean these things, what is it? HTML5, or to use its full name Hyper Text Markup Language 5, is the next iteration of the language that is used to structure and build web pages. The previous iteration, HTML 4.01 became a recommended specification in 1999, back when Windows ’98 was the de facto operating system, 56K modems were all the rage and desktop computers packed less punch than a modern mid-range smartphone. HTML4 has served us well for over a decade of huge change online, but it’s beginning to creak under the demands of truly modern web applications.

The advancements provided by HTML5 can be split in to two broad categories; new markup elements and new APIs (hang on in there).

Markup elements are the pieces of HTML that distinguish the different part of the page, in much the same way as in a word processor, you’d identify headings, paragraphs, footers and the other component parts that make up a document. HTML5 provides a new set of these elements to include audio, video, navigation items and a whole range of new form inputs for items such as email, date/time and telephone numbers.

The new markup elements allow the page author to convey far more information about the content on the page, which help search engines, aggregators and other tools to make more sense of the data that is on the page.

APIs (Application Programming Interface for the acronym fans) is the programming code that allows the web page to provide instructions to the browser, for example, ‘pause the video’. Below is an outline of a number of the key APIs included in HTML5, some of their potential uses, and where appropriate, links to live examples:

Canvas
The canvas element allows the drawing of 2D interactive shapes in the browser. A canvas can be used for drawing graphs, visual images and even implement basic games.
Example

Audio and video
Previously, all audio and video on the web has had to be implemented using a third party plugin such as Flash or QuickTime. HTML5 adds the ability to display video natively in the browser. This is likely to result in fast rendering rather than relying on a third party plugin, which is becoming a bigger issue with the shift to the mobile web, not to mention the lack of support on a number of devices for third party plugins.
Example

Offline storage
Previously, the only way websites could store information on the users' computer was through the use of cookies, which are limited to storing tiny amounts of data. HTML5 provides functionality for offline storage, which means the application can work when the user is not connected to The Internet. As more applications move online (the latest version of Microsoft Office is touted to provide an online-only version), allowing users to continue to use the application even when not connected, on a tube train or in-flight, for example, will be a huge bonus.
Example

Editing
HTML5 provides out of the box support to make any element on a page editable. It is hoped this will lead to providing far more intuitive ways for web page editors to manage the content on their websites.
Example

Drag and drop
With the increasing shift to put more applications online, HTML5 includes native functionality to create drag-and-drop components using the same mechanic as desktop applications. Previously this functionality was only available by leveraging third party libraries.
Example

Geolocation
HTML5 provides the ability for page authors to ask the browser to geolocate the user. This obvious implementation for this is for location-aware services, such as "find my nearest pizza restaurant".
Example

Custom fonts
While not strictly an HTML5 enhancement (this is part of the CSS specification, which is the technology that defines how web pages should look), many browser vendors have recently started to include support for what is known as the @font-face rule. Historically, using anything beyond a limited set of web-safe fonts such as Arial or Times New Roman required the page author to implement the text as images or rely on a third party technology such as flash to deliver the customised fonts – both of which have flaws and limitations. The @font-face rule allows any font file to be provided as an automatic download to render the text. However, most font foundries have legal restrictions on the distribution of fonts in this manner. There are a number of services emerging that have negotiated licensing deals with font foundries to allow online distribution, the most promising of which is currently the fonts.com service, which while still at ‘beta’ stage, provides access to around 7000 fonts.
Example

When will it be ready?

HTML5 is currently at a ‘Working Draft’ state with the World Wide Web Consortium (W3C), which is the primary standards organisation for the web. It is expected it will reach ‘Candidate Recommendation’ state in 2012, with it becoming a fully fledged ‘W3C Recommendation’ in 2022.

In reality, all major browser vendors have begun shipping versions of their products that contain support for a number of the enhancements provided by HTML5. Up-to-date versions of Firefox, Safari, Chrome, Opera and to a lesser extent Internet Explorer enable web page authors to take advantage of native video embedding, interactive Canvas elements and drag-and-drop.

There isn’t a golden date when the vast majority of users will have upgraded to versions of browsers that support HTML5, though we’re already at the point where around 60% of the market has some degree of HTML5 support, with around 20% of the market having support for the majority of the HTML5 enhancements.

How are glue using it?

Across the vast majority of our projects, we’ve begun to implement features of HTML5 where it makes sense to do so. Much of the functionality provided in HTML5 can be degraded in such a way that means older versions of browsers without HTML5 support will still be able to use the page, albeit without some of the newer bells and whistles. For a great case in point, Gmail, Google’s web-based email application provides the ability for users to drag-and-drop attachments on to messages. Users whose browser does not support this functionality are simply presented with the traditional file upload dialog.

We’ve launched a number of campaigns, including Only Green for the Green Party, Wrighty's XI for The Sun Newspaper and Skåne Troll Spotters Club for VisitSweden that already include a degree of HTML5 implementation.

As the market share of browsers that support HTML5 increases (we’re expecting the upgrade to Internet Explorer 9, currently penciled for 2011, to provide a big spike), we’re going to continue implementing more of the enhancements across the range of projects that we’re delivering.

Chris Blackburn, Development Director, glue Isobar