Bruce lawson-over-the-air

Web Development 2.0
Mobile, HTML5, CSS 3, DAP; beat the buzzwords with Bruce

Bruce Lawson / Over The Air / London / 10 September 2010

Opera – one browser on many devices

"Our goal is to take the one true Web and
make it available to people on their terms."
Jon S. von Tetzchner, Opera Co-founder

"All I ask is access to the full Web, for everyone, everywhere.
And some more beer."
Me

1. new web standards
2. adaptive content
3. browser as platform

new technologies you can start using today

CSS 3
font control, shadows, rounded corners,
basic animations

-moz-transition: all 0.5s ease-in-out;
-ms-transition: all 0.5s ease-in-out;
-o-transition: all 0.5s ease-in-out;
-webkit-transition: all 0.5s ease-in-out;

transition: all 0.5s ease-in-out;

HTML5 does not replace HTML 4.01

“...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

HTML5 is umbrella term:
markup elements and JavaScript APIs

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)

Demonstration of webforms

canvas = “scriptable images”

canvas has standard API methods for drawing
ctx = canvas.getContext("2d");
ctx.fillRect(x, y, width, height);
ctx.beginPath();
ctx.moveTo(x, y);
ctx.lineTo(x, y);
ctx.bezierCurveTo(x1, y1, x2, y2, c1, c2);

canvas mix with external graphics/ video
ctx = canvas.drawImage(…)

Demonstration of canvas

Scalable Vector Graphics:

● Supported in 4 modern browsers, and IE9
● Vector graphics, therefore infinitely scalable

● XML so text-based - can be made accessible

● Keeps a DOM

● Can author with Adobe Illustrator or Inkscape

<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.mp4 type=video/mp4>
<source src=movie.webm type=video/webm>

</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

Demonstration of video in Opera,
scripted controls

find out your location via JavaScript
navigator.geolocation.getCurrentPosition(success, error);

function success(position) {
/* where's Waldo? */
var lat = position.coords.latitude;
var long = position.coords.longitude;
...
}

detect if a browsers goes offline
window.addEventListener('online', function(){ … }, true);
window.addEventListener('offline', function(){ … }, true);

localStorage/sessionStorage
like cookies...
document.cookie = 'key=value; expires=Thu, 15 Feb 2010
23:59:59 UTC; path=/'
…

/* convoluted string operations go here … */

localStorage/sessionStorage
like cookies...on steroids!
localStorage.setItem(key, value);
localStorage.getItem(key);
localStorage.clear();
localStorage.key = value;
if (localStorage.key == '…') { … }
…

cache UI/resource files for offline use
<html manifest=”blah.manifest”>

CACHE MANIFEST
# send this with correct text/cache-manifest MIME
images/sprites.png
scripts/common.js
scripts/jquery.js
styles/global.css

Mobile web and why it matters
opera.com/smw

Opera Mini: 29.6 billion pages were served
and 4.1 petabytes of operator data were
compressed for Opera Mini users.

Unique users increased 114%.
July 2009 – July 2010

http://www.opera.com/smw/2010/07/

“One Web means making, as far as is reasonable, the
same information and services available to users
irrespective of the device they are using. However, it does
not mean that exactly the same information is available in
exactly the same representation across all devices.”
W3C Mobile Web Best Practices http://www.w3.org/TR/mobile-bp/#OneWeb

mobile browsers
will work ok-ish

2. separate mobile site
(m.flickr.com, mobile.mysite.com, ...)

beware browser sniffing
photo: http://www.flickr.com/photos/timdorr/2096272747/

refactored for small screen,
not dumbed down for mobile

offer users choice:
desktop or mobile?

nothing new...
fluid layout, progressive enhancement, graceful degradation

Tips for optimising for mobile/ devices:

● Use CSS3 Media Queries
● Define size of images in HTML

● Put JavaScript as far down as you can

● Reduce HTTP requests

CSS 3 Media Queries:

@media screen and
(max-device-width: 480px) {

// insert CSS rules here

}
http://www.w3.org/TR/css3-mediaqueries/

Demonstration of Media Queries

Images:

●
Images take a long time to load, so tell the browser
to leave a space for them
● If you don't, when the image finally loads, the

browser will redraw the page to fit the image in,
perhaps scrolling off screen
● Redrawing the screen wastes processor time (and

battery life)
● Some turn off images; design for accessibility

Put JS as far down the source as possible:

●
Browsers wait for JS to load. If they're at the top,
rendering pauses.
● If your JS is at the bottom of the page, the user can

read the content etc while she is waiting to interact
with the page.

Minimise HTTP requests:

●
Combine JS into one file. Same with CSS.
● Use CSS sprites to combine decorative images

● Consider encoding images directly in your page as

data URLs
● Use SVG or <canvas> for images

“…the browser run-time is perfect…you’re out
of writing for Windows Mobile, Android, S60, each
of which require testing...we want to abstract
that.

All the cool innovation is happening inside the
browser – you don’t need to write to the native
operating system anymore.”
Mobile Entertainment Market, June, 2009

W3C Widgets – application development filled
with web standards goodness,
using browser engine as platform

Anatomy of a widget
index.html, assets + config.xml,
zipped and renamed .wgt

W3C DAP
(Devices and Protocols Working Group)

Defining JavaScript APIs:

● Contacts (access address book)
● Calendar API

● Media Capture API (programmatic access to

camera/microphone)
● Messaging API (email/ SMS)

http://www.w3.org/2009/dap/

www.opera.com/developer
bruce.lawson@opera.com
twitter.com@brucel

Bruce lawson-over-the-air

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