The prospects of HTML 5
by Jon Gjengset
As a webdeveloper, feature additions and updates to commonly used libraries and languages are always exciting. Unfortunately, there is one core language of web development which has not received a proper update in years – HTML. Sure, we had XHTML, but in my opinion, that was more of a structural change than it was a rewrite of HTML. XHTML merely enforced a XML structure as well as standardize the elements used for various types of content.
This is all about to change with the development of HTML 5. HTML 5 is currently only a W3C draft, but some of its major features are already implemented in various browsers. As supposed to XHTML, HTML 5 aims to bring HTML into this century, and make it more flexible in order to satisfy the needs of today’s developers and users for multimedia content, AJAX-based user interfaces, geolocation and desktop application-like behaviour.
Brief overview of new features
HTML 5 provides a plethora of extensions and changes to traditional HTML, and to get a complete overview I suggest your read the W3C Draft which makes for very interesting reading once you can look past the RFC style. There are however a couple of features that are especially interesting:
- HTML 5 attempts to discard the remaining style-based tags of HTML, as well as remove support for frames and other “ugly” practices
- It is also developed to accommodate the way modern websites are structured, and make the structure more available to computer interpretation. For instance, instead of using divs for all sorts of site content, HTML 5 introduces specialized tags for the different sections of a webpage such as:
- A new way of handling element contexts ( i.e. moving away from the differentiation of inline and block context )
- Native Drag-and-drop and Copy-Cut-Paste APIs
- Undo history and editable content
- Support for geolocation-enabled applications
- Native multimedia tags and players to avoid the format challenges developers currently face when adding multimedia to their sites
There are several more, but again, I recommend having a look at the W3C Draft for a more in-depth description.
Draggable, copy-paste and undo
The draft also introduces two new concepts that are still under heavy debate with regards to the implementation: Native drag-and-drop support and a copy-paste API as an extension of the draggable support ( since according to the draft, you “drag” the copied content into the clipboard, and “drop” it back from the clipboard ), and an undo-redo history API.
The draggable support will remove the need for a third-party drag-n-drop library such as jQuery-UI, mootools or Prototype, and let the browser deal with this directly. Not only will this probably provide a smoother user experience, but it will most certainly enable you to build more flexible UIs since the W3C Draft dictates a lot of event triggers and intermediate controls that let you handle the dragging in high detail.
Undo history is probably the most controversial feature of the W3C Draft as no good standard definition of it has been found. From the draft one can nonetheless extract some useful indicators of how the final feature will work.
According to the current definition, the undo/redo history will store all changes to the website DOM, and allow the user to revert to previous version of the page. Most probably, it will also allow control hooks that enable you to do server actions when the user walks backwards or forwards through the history.
So, you might ask, why would I need DOM history? Well, both because you will now be able to use AJAX page loading without breaking the back button, but also because of the new attribute “contentEditable”:
Editable HTML content
HTML 5 brings a seemingly innocent attribute called “contentEditable” which, when enabled, allows the user to directly manipulate the DOM through for instance a rich-text editor, or however the browser developers decide to implement the feature. This makes for a whole new type of webpages where you can let the user completely redesign the site to his or her own liking, and where the changes may be saved for later use. And just imagine the advantages with regards to rich-text editing for blogs, articles, or indeed any other web content.
A new API has also been deviced to encourage the use of websites for portable devices or other GPS enabled computers. The API allows the website to read the users current location, as well as any updates to this. This will also enable developers to build applications that are location-sensitive, and give you data relative to your location.
Other scripting changes
- Input fields with native validation support ( type=”date, datetime, email, url, telephone…”, the “required” attribute, etc )
- Support for unlimited additional attributes for internal use as long as they are prefixed by data-
- Independent inputs – input fields may be placed outside a form tag, but still linked to the form itself
- The progress/meter tags – A way of visualizing progress or numerical values to the user without the use of ugly table/css hacks.
- Anchor ping attribute – This new attribute allows you to specify a list of URLs that should be pinged if the user clicks a link to avoid redirects to log link clicks, and make them asynchronous instead.
- The canvas tag
So, when can I use it?
What about CSS 3?
CSS 3, however amazing it might be, is not a part of the HTML 5 standard. Also, support for this the CSS 3 Draft is not very broad either. I will probably post an overview of it at a later date as well.
Further reading and sources:
The full spec: http://www.w3.org/TR/2008/WD-html5-20080122