Html5 oslo-code-camp

HTML5: why are we here?
Bruce Lawson, Opera Software

Code Camp / Oslo / 16 October 2010

Paper to W3C, 2004

We consider Web Applications to be an
important area that has not been adequately
served by existing technologies… There is a
rising threat of single-vendor solutions
addressing this problem before jointly-
developed specifications.
http://www.w3.org/2004/04/webapps-cdf-ws/papers/opera.html

Paper to W3C, 2004
●
Backwards compatibility, and a clear migration path.
●
Well-defined error handling.
●
Users should not be exposed to authoring errors.
●
Practical use: every feature that goes into the Web-
applications specifications must be justified by a practical
use case. The reverse is not necessarily true.
●Scripting is here to stay (but should be avoided where

more convenient declarative mark-up can be used).
●Avoid device-specific profiling.

●
Make the process open.

© Copyright 2004-2010 Apple Computer, Inc., Mozilla Foundation, and
Opera Software ASA.

You are granted a license to use, reproduce and create derivative works of
this document.

Design Principles - Compatibility

● Support Existing Content
● Do not Reinvent the Wheel

● Pave the Cowpaths

● Evolution Not Revolution

www.w3.org/TR/html-design-principles/

Design Principles - Utility

● Solve Real Problems
● Secure By Design

● Separation of Concerns

● DOM Consistency

Design Principles -Priority of Constituencies

Consider users over authors over implementors
over specifiers over theoretical purity.

Design Principles - Interoperability

● Well-defined Behavior
● Avoid Needless Complexity

● Handle Errors

Design Principles - Universal Access

● Media Independence
● Support World Languages

● Accessibility

HTML5 does not replace HTML 4.01

HTML5 is umbrella term:
markup elements and JavaScript APIs

Top 20 class names
1. footer 11. button
2. menu 12. main
3. style1 13. style3
4. msonormal 14. small
5. text 15. nav
6. content 16. clear
7. title 17. search
8. style2 18. style4
9. header 19. logo
10. copyright 20. body
http://devfiles.myopera.com/articles/572/classlist-url.htm

Top 20 id names
1. footer 11. search
2. content 12. nav
3. header 13. wrapper
4. logo 14. top
5. container 15. table2
6. main 16. layer2
7. table1 17. sidebar
8. menu 18. image1
9. layer1 19. banner
10. autonumber1 20. navigation
http://devfiles.myopera.com/articles/572/idlist-url.htm

Styling HTML5 elements

article, nav, header, footer
{display:block;}

document.createElement ('article');

http://html5shim.googlecode.com/svn/trunk/html5.js

Webforms – more powerful form elements

standardise commonly-used
rich form elements – without JavaScript

built-in validation
(of course you should still validate on the server)

<input type=email>
<input type=url required>
<input type=range min=10 max=100>
<input type=date min=2010-01-01 max=2010-12-31>
<input pattern="[0-9][A-Z]{3}" placeholder="9AAA">

http://people.opera.com/brucel/demo/html5-forms-demo.html

“...extending the language to better support Web
applications, since that is one of the directions the Web is
going in and is one of the areas least well served by HTML
so far. This puts HTML in direct competition with other
technologies intended for applications deployed over the
Web, in particular Flash and Silverlight.”

Ian Hickson, Editor of HTML5
http://lists.w3.org/Archives/Public/public-html/2009Jan/0215.html

<video src=video.ogv
controls
autoplay
poster=poster.jpg
width=320 height=240>
<a href=video.ogv>Download movie</a>
</video>

video format debates – Free formats vs MP4
<video controls autoplay poster=… width=… height=…>
<source src=movie.webm type=video/webm>
<source src=movie.mp4 type=video/mp4>
<source src=movie.ogv type=video/ogg>

</video>

still include fallback for old browsers
http://camendesign.com/code/video_for_everybody

video as native object...why is it important?

● “play nice” with rest of the page
● keyboard accessibility built-in

● API for controls

controlling video with JavaScript
<script>
/* grab the first video element */
var video = document.getElementsByTagName('video')[0];
/* remove the browser-supplied controls, cos we're
scripting our own */
video.removeAttribute('controls');
</script>

<video controls>
</video>

<input type=button value="play / pause"
onclick="if (video.paused) video.play(); else
video.pause()">

video accessibility
<video controls autoplay poster=… width=… height=…>
<source src=movie.mp4 type=video/mp4>
<source src=movie.ogv type=video/ogg>

<track src=subtitles.srt kind=subtitles srclang=en>


</video>

http://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#the-track-element
http://www.delphiki.com/html5/playr/

video media queries
<video controls>
<source src=hi-res.ogv media=”(min-device-width:800px)”>
<source src=lo-res.ogv>
</video>

http://dev.w3.org/html5/spec/video.html#the-source-element

Photo credits

Swinging London
http://www.flickr.com/photos/nationalarchives/3008584298/

Cute NEWT by Rob Winters @Robwinters

Sharks with lasers:
http://www.flickr.com/photos/starstreak007/3416655056/

HTML5 rocks by Alex Sexton
Used with permission

Satan from ??

All others, me

www.opera.com/developer
bruce.lawson@opera.com
www.brucelawson.co.uk
twitter.com/brucel

Html5 oslo-code-camp

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