The Yahoo User Interface Library

(YUI)

Christian Heilmann | http://wait-till-i.com | http://scriptingenabled.org

Web Directions North, Denver, Colorado, February 2009

Let’s take a walk...

...on the client side

The client side is where strange things happen.

Browsers render in fascinating and totally wrong

ways.

Random code from dubious sources interferes with your

godlike, clean and high quality code.

...and you fix more than you develop.

The web is a total mess!

The reason is that things seemingly work.

However, you are not the web and neither is your

computer.

To make things work for Yahoo we needed to find a

way to abstract these issues away from us.

And this is why we built the YUI.

It brings order to the chaos.

What chaos?

JavaScript is a part of a larger world.

This is not the copyrighted

photo you are looking for

Browser

Interaction with other technologies (CSS, Markup)

Interaction with other scripts

Interaction with the backend

Interaction with the operating system.

Interaction with the user (with unknown ability)

Interaction with bad code (a.k.a. ads)

YUI deals with all of this.

Because it has to – we built it for industrial (Yahoo)

strength.

The first thing we needed to get are some sensible

constraints.

We did this with the Graded Browser Support:

http://developer.yahoo.com/yui/articles/gbs/

This gave us a defined playground, and we were able

to start tackling the other issues.

The first thing to tackle before you can even hope to build

interfaces are browser differences in CSS.

There is no such thing as an “unstyled page”.

There is no such thing as an “unstyled page”.

Good luck working around that one.

Unless you use reset.css

http://developer.yahoo.com/yui/reset/

Starting with a blank canvas

=

good.

What about typography?

Make it work across browsers with fonts.css

http://developer.yahoo.com/yui/fonts/

Even create layouts with grids.css

http://developer.yahoo.com/yui/grids/

Grids gives you an amazingly large amount of options and

layout permutations.

YUI comes with a lot of tools to gain knowledge about what is happening under the hood

of your application.

YUI logger gives you a cross-browser console to show

values.

Death to alert()!

You can even include the logger on the fly with a

bookmarklet.

http://blog.rajatpandit.com/sandbox/yuilogger/index.html

If you need even more control, there is the YUI

profiler.

http://developer.yahoo.com/yui/profiler/

And the YUI test framework for test driven development.

http://developer.yahoo.com/yui/yuitest/

On a code level, YUI comes out-of-the-box with

namespacing.

Which – if used correctly – keeps large amounts of code readable and maintainable.

YAHOO.lang also comes with a lot of validation methods to ensure things are what they

are.

All in all YUI is a good choice for large, distributed teams.

Built on agreed standards

Separated into modules each dealing with one task (Core, DOM, Event,Animation, IO...)

Constant reporting of what is going on

Own debugging environment

YUI is a framework to build working web applications.

It allows you to create applications using tested and working widgets that extend

what HTML gives us.

AutoComplete

Button

Calendar

Charts

Container

DataTable

Layout

Menu

Rich Text

TabView

Interface W

idg

ets

Everything is fully documented.

http://developer.yahoo.com/yui/docs/

And there are almost 300 examples to look at.

http://developer.yahoo.com/yui/examples/

The controls are driven by custom events to allow for extending and monitoring

them.

All YUI components come as a debug version which log

everything that is going on to the logger.

All in all YUI allows you to build web interfaces without having to know all the pain that goes on in the browser

world.

What does the future hold?

YUI3

http://developer.yahoo.com/yui/3/

Include on demand

Multiple sandboxed instances in a page

Modularity on CSS level (per element reset)

Every event is a custom event

Screen reader compatible widgets.

Widgets extendable with plugins

Framework (SDK) for own compatible widgets.

The elevator lift pitchYUI is the system that Yahoo uses to build its web sites. It is constantly tested to work for the largest amount of users, free, open source and covers everything from design patterns to out-of-the-box widgets. It is modular and you can use only what you need. You can either host it yourself or get it from a network of distributed servers.

http://isithackday.com/hacks/delhi/

Christian Heilmann

http://wait-till-i.com

http://scriptingenabled.org

http://twitter.com/codepo8

T H A N K S !