HTML5 and Google Chrome - DevFest09

HTML 5 and
Google Chrome
Mihai Ionescu
Developer Advocate, Google

Browsers Started a Revolution that Continues
• In 1995 Netscape introduced JavaScript
• In 1999, Microsoft introduces XMLHTTP
• In 2002, Mozilla 1.0 includes XMLHttpRequest natively

... Then web applications started taking off ...

• In 2004, Gmail launches as a beta
• In 2005, AJAX takes off (e.g. Google Maps)

... Now web applications are demanding more capabilities

User Experience The Web is Developing Fast…

XHR
Native Web
CSS

DOM
HTML

1990 – 2008 Q109 Q209 Q309 Q409

The Web is Developing Fast…

Android 2.0: Oct 26, 2009

Chrome 3.0: Sep 15, 2009

Firefox 3.5: June 30, 2009
User Experience

iPhone 3.0: June 30, 2009

Safari 4.0: Jun 08, 2009

Palm Pre: June 06, 2009
Chrome 2.0: May 21, 2009
Android 1.5: Apr 13, 2009

XHR
Opera Labs: Mar 26, 2009 Native Web
CSS

DOM
HTML

1990 – 2008 Q109 Q209 Q309 Q409

The web is also getting faster
160

140
SunSpider Runs Per Minute

120

100 100x improvement
in JavaScript performance
80

60

40

20

00
2001 2003 2005 2007 2008 2009

What New Capabilities do Webapps Need?
• Plugins currently address some needs, others are still not well
addressed
– Playing video
– Webcam / microphone access
– Better file uploads
– Geolocation
– Offline abilities
– 3D
– Positional and multi-channel audio
– Drag and drop of content and files into and out of webapps
• Some of these capabilities are working their way through
standards process

Our Goal
• Empower web applications
– If a native app can do it, why can’t a webapp?
– Can we build upon webapps strengths?
• Understand what new capabilities are needed
– Talking to application developers (you!)
– Figure out what native applications people run
• And what web applications serve similar purposes
• And what native applications have no web equivalent
• Implement (we’re going full speed ahead...)
– We prototyped in Gears
– Now we’re implementing natively in Google Chrome
• Standardize

<canvas>
• One of the first HTML5 additions to be implemented by
browsers – in Safari, then Firefox and Opera. (We got it for
free in Google Chrome from WebKit).
• Provides a surface on which you can draw 2D images
• Talk of extending the model for 3D (more later)

// canvas is a reference to a <canvas> element
var context = canvas.getContext('2d');
context.fillRect(0,0,50,50);
canvas.setAttribute('width', '300'); // clears the canvas
context.fillRect(0,100,50,50);
canvas.width = canvas.width; // clears the canvas
context.fillRect(100,0,50,50); // only this square remains

(reproduced from http://www.whatwg.org/specs/web-apps/current-
work/#canvas with permission)

<video> / <audio>
• Allows a page to natively play video / audio
– No plugins required
– As simple as including an image - <audio src=“song.mp3”>
• Has built-in playback controls
– Stop
– Pause
– Play
• Scriptable, in case you want your own dynamic control
• Implemented in WebKit / Chrome

Local Data Store
• Provides a way to store data client side
• Useful for many classes of applications, especially in
conjunction with offline capabilities
• 2 main APIs provided: a database API (exposing a SQLite
database) and a structured storage api (key/value pairs)
• Implementation under way in Google Chrome, already
working in WebKit.
db.transaction(function(tx) {
tx.executeSql('SELECT * FROM MyTable', [],
function(tx, rs) {
for (var i = 0; i < rs.rows.length; ++i) {
var row = rs.rows.item(i);
DoSomething(row['column']);
}
});
});

Workers
• Workers provide web apps with a means for concurrency
• Can offload heavy computation onto a separate thread so
your app doesn’t block
• Come in 3 flavors:
– Dedicated (think: bound to a single tab)
– Shared (shared among multiple windows in an origin)
– Persistent (run when the browser is “closed”)
main.js:
var worker = new Worker(‘extra_work.js');
worker.onmessage = function (event) { alert(event.data); };

extra_work.js:
// do some work; when done post message.
postMessage(some_data);

Application Cache
• Application cache solves the problem of how to make it such
that one can load an application URL while offline and it just
“works”
• Web pages can provide a “manifest” of files that should be
cached locally
• These pages can be accessed offline
• Enables web pages to work without the user being connected
to the Internet
• Implemented in WebKit, implementation ongoing in Google
Chrome

Web Sockets
• Allows bi-directional communication between client and
server in a cleaner, more efficient form than hanging gets
(or a series of XMLHttpRequests)
• Intended to be as close as possible to just exposing raw
TCP/IP to JavaScript given the constraints of the Web.
• Available in dev channel

var socket = new WebSocket(location);
socket.onopen = function(event) {
socket.postMessage(“Hello, WebSocket”);}
socket.onmessage =function(event) { alert(event.data); }
socket.onclose = function(event) { alert(“closed”); }

Notifications
• Alert() dialogs are annoying, modal, and not a great user
experience
• Provide a way to do less intrusive event notifications
• Work regardless of what tab / window has focus
• Provide more flexibility than an alert() dialog
• Prototype available in Webkit / Chrome
• Standardization discussions ongoing
var notify = window.webkitNotifications.createNotification(
icon, title, text);
notify.show();

notify.ondisplay = function() { alert(‘ondisplay’); };
notify.onclose = function() { alert(‘onclose’); };

3D APIs
• WebGL (Canvas 3D), developed by Mozilla, is a command-
mode API that allows developers to make OpenGL calls via
JavaScript
• O3D is an effort by Google to develop a retain-mode API
where developers can build up a scene graph and manipulate
via JavaScript, also hardware accelerated
• Discussion on the web and in standards bodies to follow

Geolocation
• Make JavaScript APIs from the client to figure out where you
are
• Location info from GPS, IP address, Bluetooth, cell towers
• Optionally share your location with trusted parties
• Watch the user’s position as it changes over time
• Implementation ongoing in Chrome

// Single position request.
navigator.geolocation.getCurrentPosition(successCallback);

// Request position updates.
navigator.geolocation.watchPosition(successCallback);

And So Much More…
• There’s much work ahead.
• Some is well defined
– File API
– Forms2
– WebFont @font-face
• Many things less defined
– P2p APIs
– Better drag + drop support
– Webcam / Microphone access
– O/S integration (protocol / file extension handlers and more)
– And more

Chrome HTML 5 in a Nutshell
Video, Audio, Workers
Additional APIs
available in Chrome 3.
(TBD) to better
Websockets in dev channel. support web
applications
Appcache, More work
Notifications, -Geolocation
Database, , Web GL,
Local storage, File API
in dev channel

Q4 Q1 / 2010 Q2 Q3

HTML 5 Native Support

Canvas

Video

….

Local storage

Web workers

HTML 5 Native Support

with
Chrome Frame

Canvas

Video

….

Local storage

Web workers

HTML 5 Resources
www.whatwg.org/html5

www.chromium.org/developers/web-platform-status

blog.chromium.org

diveintohtml5.org

quirksmode.org

HTML5 and Google Chrome - DevFest09

HTML5 and Google Chrome - DevFest09

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