HTML5: A brave new world of markup

HTML5: A brave new
world of markup
Chris Mills, Opera Software

Slides available on http://slideshare.net/chrisdavidmills

Who the hell am I?
‣ Opera open standards evangelist and tech writer
‣ Telling the world about open standards & Opera
‣ Improving web education
‣ Drinking beer & saving the world before morning
‣ Drumming in a heavy metal band

What is HTML5?
A new HTML spec that defines:
‣ New semantic elements
‣ New features such as native video, more
powerful forms, web sockets
‣ New APIs for controlling such features
‣ Error handling, and other such useful things

Or according to the W3C...
‣ HTML5
‣ CSS3, WOFF
‣ SVG, SMIL, WebGL
‣ Geolocation, WAC
‣ Indexed DB, File API
‣ Server-sent events
‣ Web workers, XHR2
‣ & every other bloody open standard under the
sun!

A brief history of HTML
‣ HTML first proposed 1989-1991
‣ HTML3 first standardised in 1995
‣ HTML 4.01 standardised in 1999
‣ Corrections submitted in 2001

HTML5 history
‣ W3C decided the future was XHTML
‣ This didn’t go down well, and no-one gave a rat’s
ass about XHTML2
‣ HTML5 (was web applications 1.0) started by
WHATWG in 2004ish
‣ Adopted by W3C 2008
‣ WHATWG version became versionless in 2011

When should I use it?
Now!
‣ Most modern browsers support most of this stuff
now
‣ Workarounds are perfectly possible
‣ You are already using HTML5 by using HTML4.x
‣ Don’t wait till it’s completely finished

The UK road system is
never finished...

http://www.ﬂickr.com/photos/50014762@N03/4632637811/

There’s nothing wrong with
HTML4...

http://www.ﬂickr.com/photos/birdfarm/519230710/

But HTML5 has more bling!
As if! Not publishing this one...

HTML5 does not replace
HTML4
‣ It’s backwards compatible
‣ It fills up holes
‣ It adds new markup and APIs
‣ It competes with proprietary/plugin technology

HTML5 features
‣ More accurate semantics (eg <header>,
<footer>)
‣ Better forms
‣ <video>
‣ <canvas>

HTML5 features
‣ Drag and drop
‣ Web workers
‣ Web storage, webdb, AppCache
‣ ...aaand more.

Not HTML5, but as good as
‣ Geolocation
‣ Web sockets

HTML is the new HTML5?
In January 2011, Ian Hickson announced that the
WHATWG HTML5 spec was dropping its version
number, and becoming a living spec that could
keep being added to, as more features came to
fruition. The W3C version is keeping its version
number, and acting as a snapshot.

New syntax: better
semantics

http://www.ﬂickr.com/photos/zscheyge/49012397/

HTML5 doctype
<!doctype html>

Typical website structure
<div id=”header”></div>
<div id=”nav”></div>
<div id=”main”>
  <div class=”article”></div>
  <div class=”article”></div>
    ...
</div>
<div id=”footer”></div>

Most common classes and
IDs?
Ian Hickson did a study at Google of the most
common classes and IDs on the Web. so did
Opera
‣ http://code.google.com/webstats/2005-12/
classes.html
‣ http://devfiles.myopera.com/articles/572/idlist-
url.htm
‣ http://devfiles.myopera.com/articles/572/
classlist-url.htm

HTML5 update
<header></header>
<nav></nav>
<section id=”main”>
  <article></article>
  <article></article>
    ...
</section>
<footer></footer>

<header> and <footer>
<header>
  <h1>Top level heading</h1>
</header>
    
<footer>
  <p>©2011 Chris Mills examples</p>
</footer>

<nav>
<nav>
  <ul>
    <li><a href=”#article1”>First article</a></li>
    <li><a href=”#article2”>Second article</a></li>
    <li><a href=”#article3”>Third article</a></li>
  </ul>
</nav>

<aside>
<aside>
  <h2>About the author</h2>
    <p>Chris Mills is a front‐end bling junkie
     working for Opera Software...</p>
</aside>

<time>
<p>Article published on the 
  <time datetime=”2011‐03‐12T09:48”>
    12th March 2011, at 9:48am
  </time>
</p>

<hgroup>
<hgroup>
  <h1>Top level heading</h1>
  <h2>This is a really descriptive subtitle</h2>
</hgroup>

<figure> and <figcaption>
<figure>
  <img src=”bear.jpg”
       alt=”this is the bear that I wrestled” />
  <figcaption>This is the bear that I
  wrestled.</figcaption>
</figure>

Where does this leave the
humble <div>?
Use it for anything that isn’t covered by other new
elements, and is just a general grouping, e.g. for
styling purposes, for which you don’t want to
create a new section. An intro <div>, perhaps?

The HTML5 outlining
algorithm
Heading/section hierarchy based on sectioning
element hierarchy, not <hx> elements used
‣ No longer limited to six heading levels
‣ Hierarchy stays correct when syndicated
‣ You can retain HTML4 heading levels for
backwards compatibility

The HTML5 outlining
algorithm
<h1>My title</h1>
<div>
  <h2>My subtitle</h2>
</div>

<h1>My title</h1>
<section>
  <h2>My subtitle</h2>
</section>

New semantics rock!
‣ Better machine readability
‣ Better interoperability
‣ Better accessibility (once screen readers catch
up; WAI-ARIA is a stopgap)
‣ Leaner markup that is easier to style
‣ More in keeping with what real webdevs do

Browsers don’t ACTUALLY
support these ... yet
But we can get them displaying ok
‣ You can style any element with CSS, even if the
browser doesn’t recognise it
‣ Give all the structural elements display: block;
‣ IE also needs some scripting:
createElement(‘article’);
‣ HTML5Shiv sorts it better

How do we get this working
across browsers?
article, section, aside {
  display: block;
}

How do we get this working
across browsers?
<script>
  document.createElement('article');
  document.createElement('section');
  document.createElement('aside');    
</script>

Lax syntax?
Some say that HTML5 syntax is really lax — you:
‣ don’t need to quote attributes
‣ can minimize attributes
‣ don’t need to self close
‣ can mix upper and lower case
‣ You don’t even need to include <html>, <head>
and <body>!

Lax syntax?
But this more accurately reflects what real
developers do, rather than what the XHTML spec
THINKS they should
‣ You can use the style you want (although you
should stick to some best practices)
‣ The browser fills in a lot of this stuff
‣ The HTML5 spec defines how errors should be
handled

HTML5 forms
Previously called Web Forms 2.0
‣ More powerful form controls
‣ Built-in validation

Slider
<input type=”range” />

Date-time controls
<input type=date>
<input type=datetime>
<input type=week>
<input type=month>

Search boxes
<input type=search>

Datalist
<input type=”text” list=”mydata”>
<datalist id=”mydata”>
  <option label=”Mr” value=”Mister”>
  <option label=”Mrs” value=”Mistress”>
  <option label=”Ms” value=”Miss”>
</datalist>

Other new input types
<input type=”email”>
<input type=”url”>
<input type=”tel”>

Validation
Form validation used to be horrendous

function validate() {  

 var str = “”;  

 var elements = document.getElementsByTagName('input');  

 

 // loop through all input elements in form  

 for(var i = 0; i < elements.length; i++) {  

 

   // check if element is mandatory; ie has a pattern   

   var pattern = elements.item(i).getAttribute('pattern');  

   if (pattern != null) {  

     var value = elements.item(i).value;  

 

     // validate the value of this element, using its defined pattern  

     var offendingChar = value.match(pattern);  

 

     // if an invalid character is found or the element was left empty  

     if(offendingChar != null || value.length == 0) {  

 

       // add up all error messages  

       str += elements.item(i).getAttribute('errorMsg') + “n” +  

              “Found this illegal value: '” + offendingChar + “' n”;  

 

       // notify user by changing background color, in this case to red  

       elements.item(i).style.background = “red”;   

     }  

   }  

 }   

 

 if (str != “”) {  

   // do not submit the form  

   alert(”ERROR ALERT!!n” +str);   

   return false;  

 } else {  

   // form values are valid; submit

HTML5 gives you this
<input type=”text” required>

And this
<input type=”text” required 
       pattern=”[A‐z]{1,20} [A‐z]{1,20}”>

Other new attributes
autofocus
placeholder
min
max
step

autofocus, placeholder
<input type=”text” ... placeholder=”Enter first 
then last name” autofocus />

min, max and step
<input type=”range” ... min=”1.00” max=”2.50” 
step=”0.01” value=”1” />

New output mechanisms
<output>
<progress>
<meter>

<output>
<input type=”range” id=”height” name=”height” 
required min=”1.00” max=”2.50” step=”0.01” 
value=”1” />
<output onforminput=”value=height.value” 
for=”height”>1</output>m

<canvas>
Scriptable graphics
‣ Standard API for drawing
‣ Supporting across all modern browsers

The basics
<canvas id=”canvas” width=”400” height=”300”>
  ...fallback...
</canvas>

The basics
var ctx = 
document.getElementById('canvas').getContext('2d');

ctx.fillStyle
ctx.fillRect

<canvas> examples
‣ http://dev.opera.com/articles/view/html-5-
canvas-the-basics/
‣ http://ejohn.org/blog/processingjs/
‣ http://www.hakim.se/experiments/
‣ http://www.canvasdemos.com/
‣ http://people.opera.com/patrickl/experiments/
canvas/particle/3/

<video> and <audio>
New elements, plus new API for controlling audio
and video

The old school way
<object width=”425” height=”344”>
<param name=”movie”  value=”http://www.example.com/
v/LtfQg4KkR88&hl=en&fs=1”></param>
<param name=”allowFullScreen” value=”true”></param>
<embed src=”http://www.example.com/v/
LtfQg4KkR88&hl=en&fs=1”
  type=”application/x‐shockwave‐flash”
  allowfullscreen=”true” width=”425” 
height=”344”></embed>
</object>

The badass sexy new way
<video></video>

Point to the video
<video src=”video.webm”>
</video>

width and height
<video src=”video.webm”
       width=”480px”
       height=”283px”>
</video>

Add controls
       width=”480px”
       height=”283px”
       controls>
</video>

A poster to front the video
       width=”480px”
       height=”283px”
       controls
       poster=”video.jpg”>
</video>

autoplay and loop
       width=”480px”
       height=”283px”
       poster=”poster.png”
       autoplay
       loop>
</video>

Fallback
       width=”480px”
       height=”283px”
       poster=”poster.png”
       autoplay
       loop>
  <p>Your browser doesn’t support HTML5 video. <a 
href=”myVideo.webm”>Download the video instead</
a>.</p>
</video>

Native <video> is awesome!
‣ Works well with other open standards
‣ Built-in keyboard accessibility
‣ API for customizing controls, etc.
‣ Doesn’t require plugins!

What’s bad about <video>?
‣ People can download <video> easily
‣ That old cross browser chestnut
‣ Captioning and suchlike is at an early stage

Browser support
‣ Opera: Ogg since 10.5, WebM since 10.60
‣ Firefox: Ogg since 3.5, WebM since 4
‣ Chrome: Ogg since 3.0, WebM since 6.0
‣ IE: MP4 since 9.0
‣ Safari: MP4 + anything else Quicktime supports
since 3.0

Adding different formats
<source src=”video.mp4” type=”video/mp4”>
<source src=”video.webm” type=”video/webm”>

Adding a Flash fallback
<object type=”application/x‐shockwave‐flash” 
data=”player.swf” width=”480” height=”283”>
  <param name=”allowfullscreen” value=”true”>
  <param name=”allowscriptaccess” value=”always”>
  <param name=”flashvars” value=”file=video.mp4”>   
 
  <!‐‐[if IE]><param name=”movie” 
value=”player.swf”><![endif]‐‐>
  <img src=”video.jpg” width=”480” height=”283” 
alt=”Video”>
</object>

Some stuff is not as easy
‣ WebSRT exists for captioning, but is at an early
stage
‣ There is no easy cue points mechanism
‣ But such problems can be solved using
JavaScript

Video captions #1
<video></video>
<div class=transcript>
     <p>Hello, Good Evening and Welcome</p> 
     <p>Tonight on the Jeremy Kyle show ...</p> 
          ....
</div>

Video captions #2
<div class=transcript>
      <p><span>Hello, Good Evening</span>
      <span> and Welcome.</span></p> 
      <p><span>Tonight on the Jeremy Kyle 
show ...</span> 
      </p> 
          .... 
</div>

Video captions #3
<p>
   <span data‐begin=1 data‐end=2.4>Hello, Good 
Evening</span> 
   <span data‐begin=3 data‐end=3.6> and Welcome.</
span>
</p>

Video captions #4
function timeupdate() { 
   var v = document.querySelector('video'); 
   var now = v.currentTime;  …
} 

<video width=600 src=synergy.webm 
ontimeupdate=timeupdate()>

So much more to cover!
‣ AppCache
‣ WebSQL
‣ Web sockets
‣ Web workers
‣ Web storage

Thanks for listening!
‣ cmills@opera.com
‣ @chrisdavidmills
‣ http://dev.opera.com/articles/tags/html5/
‣ http://html5doctor.com

HTML5: A brave new world of markup

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