jQueryTO: State of jQuery March 2013

The State of jQuery
Dave Methvin
President, jQuery Foundation
March, 2013

How It All Started
Jan 2006: The birth of jQuery

Seven Years of Good Luck

Feb 2013: jQuery core is used by 64
percent of the top 10,000 sites

The jQuery Foundation
• Created in March 2012

The jQuery Foundation
• Created in March 2012
• Coordinates the work of jQuery team
members and volunteers

The jQuery Foundation Is...
• A non-profit organization
o Volunteer board of directors
o Volunteer president (thats me)
o A few paid staff, mainly devs/ops
• Funded by
o Conferences
o Donations – http://jquery.org/donate
o Memberships
o YOU or your company can be a member
 http://jquery.org/join

jQuery Foundation
• Founding Members

jQuery Foundation
• Gold Members

The jQuery Foundation's Work
• Organize/fund work on the projects
• Advocate for web developer needs
o W3C web standards
o ECMA TC39 JavaScript standards
• Run two US conferences annually
• License conferences worldwide

jQuery Foundation Projects
• http://github.com/jquery
• jQuery Core
• jQuery UI
• jQuery Mobile
• Sizzle selector engine
• QUnit unit test framework
• jQuery Migrate plugin
• TestSwarm CI testing
• Documentation sites

Join The Community
• It’s all on Github – not just the code
• File an issue when you see a problem
• Make pull requests against docs
• Join our forum and share knowledge

The jQuery Core Library Plan
• jQuery 1.9 vs. 2.0
o jQuery 1.x still supports IE 6/7/8
o jQuery 2.x supports modern browsers
o The two versions stay in API sync
o Both branches maintained by the team
• Heavily publicized changes during 2012
• Released several public betas
• Shipped jQuery 1.9 in January

What We Learned (the Hard Way)

Far too many people
are using "latest"
versions in live sites!

NEVER HOTLINK:

http://code.jquery.com/jquery-latest.js

http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.js

jQuery Migrate Plugin
• Identifies things your code is doing that
jQuery 1.9/2.0 don't support anymore
• Actually changes jQuery back to pre-1.9
behavior so older code just works
• Lets you use jQuery 1.9/2.0 with code
that hasn't been upgraded yet
• Documentation gives advice on how to
remediate the issue

jQuery Migrate Warnings
• Shown in the uncompressed version
• Problem and solutions documented

Shut-Up-and-Fix-It Mode
Include the minified version of the plugin
and no warnings appear

What We Broke Fixed, and Why
• Removed $.browser
• Removed .live()
• Fixed $.parseJSON

Why $.browser Deserves To Go
• Usually the wrong inference
• Often assumes future browsers and
versions will be broken the same way
• Horribly misused and misunderstood

Why You Don't Assume Browsers
Chrome added focusin/out two years ago!

Browser Name is Only a BRAND
Opera just announced their future
products will be based on the WebKit
engine, not their own Presto engine.

Internet Explorer's Disguises
• IE can emulate older versions via
<meta name="X-UA-Compatible“ …>
• Can be accidentally lobotomized via that
confounded Address Bar button
• Browser version in the UA string does not
represent the real version

The Enemy!

... copy/pasta is bad!
Not fixing the problem, no code attribution

... copy/pasta is bad!
Use jQuery Migrate or (better) Modernizr!

What's Wrong With .live()?
• It's like global variables, but for events
• Every event that occurs must bubble to
document before it can be processed
• Processing events can be expensive,
especially on deep documents
• Still easy to process events globally:
o $(document).on("click", "a", linkyClicky);

What's Wrong With .live()?
• Doesn't work well on iPhone/iPad!
• iOS doesn't bubble touch events all the
way to document
• Delegated touch events must be
processed below the <body> element

Letting all events bubble to document
destroys the usefulness of the event
propagation model

Optimize Your Selectors
Original line:
$(".dialog .close").live("click", ...

Direct replacement (poor):
$(document).on("click", ".dialog .close" ...

Optimized replacement:
$(".dialog").on("click", ".close", ...

JSON Should Be JSON
The Bug:
• Before 1.9, $.parseJSON("") returned
null but it's not valid JSON

The Fix:
• In 1.9, $.parseJSON("") is an error

The Result: PANIC
• We called invalid JSON invalid.
• We're also out of coffee.

The Moral of the Story

In jQuery, every change is
a breaking change for
some poor developer.

The Other Moral of the Story

Nobody tries the jQuery
alpha and beta builds.

Big News: jQuery 2.0 Beta 2
• Released yesterday -- please try it!
• Custom builds can shrink size
• Bare-bones selector engine option
o Basically, just querySelectorAll
• How small?
o Normal build: 28KB minified and gzipped
o Blog example: 17KB
o Tiniest build: 14KB

jQuery 2.0: README.NOW
Making a public web site?
You don't need 2.0 right now!

jQuery 2.0 is a good fit for:
• Chrome or Firefox plugins
• node.js apps (jsdom, Cheerio)
• Windows 8 Store ("Modern/Metro") apps
• PhoneGap (iPhone/Android/BlackBerry)
• Apps using UIWebKit or WebBrowser

jQuery 2.0 is Forward Looking
• The jQuery team supports both 1.9 and
2.0; there isn't a problem of using an
"unsupported version"
• Since 1.x/2.x APIs are the same, there is
no problem in using 1.x exclusively on a
public web site -- it's recommended
• You can detect platforms and include 1.9
or 2.0, but beware of your code or
plugins using undocumented semantics!

Old Android Browsers Lack ES5
EcmaScript 5 is was the 2.0 baseline

(-:

:-(

Questions?

Email: dave@jquery.com
Twitter: @davemethvin
GitHub: @dmethvin
IRC (Freenode): DaveMethvin #jquery-dev

jQueryTO: State of jQuery March 2013

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