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An introduction to YUI and some examples of how to use it to solve daily problems in web design. A talk given at the University in Bucharest and partly re-hashed on the flight from my Ajax Experience talk.
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Introducing YUI
Christian Heilmann
Bucharest, Romania, November 2008
Hello there, I am Chris.
I am here today to talk about the Yahoo User Interface
library (YUI)http://developer.yahoo.com/yui/
What is the most annoying thing about web
development?
The undefined environment.
This is also the coolest thing about web development.
Don’t ever delude yourself into thinking you can control what people see when they
visit your web products.
However, you want your products to work.
The working bit is what I want to talk to you about.
When you start writing a web document, you use HTML and
hope browsers do things right.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html lang="en"><head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Here’s my title</title> <meta name="description" content="Description"></head><body></body></html>
The right DOCTYPE, encoding and language is a great start.
This is an unstyled document, right?
Wrong.
There is no such thing as an unstyled document.
There is no such thing as an “unstyled page”.
This differs from browser to browser and can be *very*
annoying!
Which is why YUI offers you reset.css
http://developer.yahoo.com/yui/reset/
Starting with a blank canvas is a good start.
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/
All of this with one line of code pulling a document
from the web.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html lang="en"><head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Here’s my title</title> <meta name="description" content="Description"> <link rel="stylesheet" href="http://yui.yahooapis.com/2.5.1/build/reset-fonts-grids/reset-fonts-grids.css" type="text/css"></head><body></body></html>
What if that file is not available?
First of all, this is not a single server, but a world-wide
network of servers.
Visitors of your site will get the files from the server geographically located
nearest to them.
This is Yahoo’s network, but you can also use Google’s!
http://yuiblog.com/blog/2008/11/19/yui-google/
http://developer.yahoo.com/yui/articles/hosting/
If you like full control, then you can also host the files
yourself (this will also make them work off-line!)
Let’s play with grids a bit.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html lang="en"><head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Here’s my title</title> <link rel="stylesheet" href="http://yui.yahooapis.com/2.5.1/build/reset-fonts-grids/reset-fonts-grids.css" type="text/css"></head><body>
<div id="doc" class="yui-t4"> <div id="hd">Header</div> <div id="bd"> <div id="yui-main"> <div class="yui-b"> Main section </div> </div> <div class="yui-b"> Sidebar </div> </div> <div id="ft"><p>Footer</p></div></div></body></html>
You divide the document in three parts: a head, a body
and a footer.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html lang="en"><head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Here’s my title</title> <link rel="stylesheet" href="http://yui.yahooapis.com/2.5.1/build/reset-fonts-grids/reset-fonts-grids.css" type="text/css"></head><body>
<div id="doc" class="yui-t4"> <div id="hd">Header</div> <div id="bd"> <div id="yui-main"> <div class="yui-b"> Main section </div> </div> <div class="yui-b">
Sidebar </div> </div> <div id="ft"><p>Footer</p></div></div></body></html>
You then define a side bar and a main part.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html lang="en"><head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Here’s my title</title> <link rel="stylesheet" href="http://yui.yahooapis.com/2.5.1/build/reset-fonts-grids/reset-fonts-grids.css" type="text/css"></head><body>
<div id="doc" class="yui-t4"> <div id="hd">Header</div> <div id="bd"> <div id="yui-main"> <div class="yui-b"> Main section </div> </div> <div class="yui-b">
Sidebar </div> </div> <div id="ft"><p>Footer</p></div></div></body></html>
Both are identical, the only difference is that the main
part has to be wrapped in a DIV with the ID “yui-main”.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html lang="en"><head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Here’s my title</title> <link rel="stylesheet" href="http://yui.yahooapis.com/2.5.1/build/reset-fonts-grids/reset-fonts-grids.css" type="text/css"></head><body>
<div id="doc" class="yui-t4"> <div id="hd">Header</div> <div id="bd"> <div id="yui-main"> <div class="yui-b"> Main section </div> </div> <div class="yui-b">
Sidebar </div> </div> <div id="ft"><p>Footer</p></div></div></body></html>
The order of the two doesn’t matter!
The sidebar is a predefined width, the main section takes
up the rest of the space.
You define the overall width of the document with an ID
and the location and width of the sidebar with a class on
the containing DIV.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html lang="en"><head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Here’s my title</title> <link rel="stylesheet" href="http://yui.yahooapis.com/2.5.1/build/reset-fonts-grids/reset-fonts-grids.css" type="text/css"></head><body>
<div id="doc" class="yui-t4"> <div id="hd">Header</div> <div id="bd"> <div id="yui-main"> <div class="yui-b"> Main section </div> </div> <div class="yui-b">
Sidebar </div> </div> <div id="ft"><p>Footer</p></div></div></body></html>
#doc = 750px
#doc2 = 950px
#doc3 = 100%
#doc4 = 974px
.yui-t1 = left 160px
.yui-t2 = left 180px
.yui-t3 = left 300px
.yui-t4 = right 180px
.yui-t5 = right 240px
.yui-t6 = right 300px
ID and width class, side and width
You can add grid units inside the main section to divide it
into horizontal columns.
Check the docs at:http://developer.yahoo.com/yui/grids
Or if you are lazy...
Use the grids builder:
http://developer.yahoo.com/yui/grids/builder/
So where does this work?
In all the browsers Yahoo has to support.
Which are defined in our graded browser support:
http://developer.yahoo.com/yui/articles/gbs/
What if a new browser comes around?
Chances are very high Yahoo will have to support it...
...so check the YUI blog and update your YUI CSS include.
http://yuiblog.com
Much faster than fixing everything yourself, right?
What if HTML is not rich enough for your needs?
Almost all *free* and *big* JavaScript libraries come
with widgets that work and are proven in the market.
YUI is of course one of them.
AutoComplete
Button
Calendar
Carousel beta
Charts [experimental]
Color Picker
Container
DataTable
ImageCropper beta
Layout Manager
Menu
Paginator
Rich Text Editor
Slider
TabView
TreeView
Uploader [experimental]
http://ui.jquery.com/
http://ui.jquery.comhttp://developer.yahoo.com/yui/
Of course the other thing the YUI makes a lot easier is
using JavaScript.
Both by fixing annoying browser bugs and by offering
convenience methods.
For example:
Wouldn’t it be cool to not know when to use which size
of the grid automatically?
You can do that using YUI DOM.
http://developer.yahoo.com/yui/dom
Using the DOM component, I can read out what happens in
the browser.
I can get the dimensions of the window, the browser and of
any element in the document - regardless of its positioning.
Thus I can create a YUI grid that works with all kind of different browsers sizes.
http://yuiblog.com/blog/2008/06/25/autogrids
YAHOO.example.autoGrid = function(){ var container = YAHOO.util.Dom.get('doc') || YAHOO.util.Dom.get('doc2') || YAHOO.util.Dom.get('doc4') || YAHOO.util.Dom.get('doc3') || YAHOO.util.Dom.get('doc-custom'); if(container){ var sidebar = null; var classes = container.className; if(classes.match(/yui-t[1-3]|yui-left/)){ var sidebar = 'left'; } if(classes.match(/yui-t[4-6]|yui-right/)){ var sidebar = 'right'; } function switchGrid(){ var currentWidth = YAHOO.util.Dom.getViewportWidth();
if(currentWidth > 950){ container.id = 'doc2'; if(sidebar){ container.className = sidebar === 'left' ? 'yui-t3' : 'yui-t6'; } } if(currentWidth < 950){ container.id = 'doc'; if(sidebar){ container.className = sidebar === 'left' ? 'yui-t2' : 'yui-t5'; } } if(currentWidth < 760){ container.id = 'doc3'; if(sidebar){ container.className = sidebar === 'left' ? 'yui-t1' : 'yui-t4'; } }
if(currentWidth < 600){ container.id = 'doc3'; container.className = ''; } }; switchGrid(); function throttle(method, scope) { clearTimeout(method._tId); method._tId= setTimeout(function(){ method.call(scope); }, 100); }; YAHOO.util.Event.on(window,'resize',function(){ throttle(YAHOO.example.autoGrid.switchGrid,window); });
}; return { switchGrid:switchGrid };}();
What about monitoring the size of an element?
position:fixed is sexy!
It can however also render your site impossible to use.
var YD = YAHOO.util.Dom; YAHOO.util.Event.onDOMReady(toggleMenu); YAHOO.util.Event.on(window,'resize',function(){ toggleMenu(); }); function toggleMenu(){ var sidebar = YD.getRegion('sb'); var browser = YD.getViewportHeight(); YD.setStyle('sb','position', browser < sidebar.bottom ? 'static' : 'fixed' ); }
The DOM stepchild: Region
Using Region I can find out the dimensions of an element.
I can also find the region that is big enough to include two
regions, or the one that is the intersection of the two.
region example
YAHOO.util.Event.onDOMReady(function(){ var YD = YAHOO.util.Dom; var r1 = YD.getRegion('region-one'); var r2 = YD.getRegion('region-two'); var i = r1.intersect(r2); var u = r1.union(r2); var intersect = document.createElement('div'); document.body.appendChild(intersect); YD.setStyle(intersect,'position','absolute'); YD.setStyle(intersect,'background','#c0c'); YD.setStyle(intersect,'width',i.right-i.left + 'px'); YD.setStyle(intersect,'height',i.bottom-i.top + 'px'); YD.setStyle(intersect,'z-index',100); YD.setXY(intersect,i);
var union = document.createElement('div'); document.body.appendChild(union); YD.setStyle(union,'position','absolute'); YD.setStyle(union,'background','#000'); YD.setStyle(union,'opacity',.5); YD.setStyle(union,'width',u.right-u.left + 'px'); YD.setStyle(union,'height',u.bottom-u.top + 'px'); YD.setStyle(union,'z-index',90); YD.setXY(union,u); });
This gives me full control to avoid any overlap!
What about things the browser does not tell me?
Wouldn’t it be cool to find out when the font is resized?
http://alistapart.com/articles/fontresizing
You can detect the font size in several ways:
Include an element with a known size in ems and read its
offsetHeight and offsetWidth in an interval...
...or use an iframe with em sizing off-screen and subscribe
to its resize event.
Or use the YUI container module anywhere on your
page... :)
YAHOO.namespace('example.container'); YAHOO.util.Event.onDOMReady(function(){ YAHOO.example.container.module1 = new YAHOO.widget.Panel( 'module1', { close:true, draggable:true, constraintoviewport:true } ); YAHOO.example.container.module1.render(); YAHOO.widget.Module.textResizeEvent.subscribe( function(o){ console.log('Text has been resized!') } ); });
YAHOO.namespace('example.container'); YAHOO.util.Event.onDOMReady(function(){ YAHOO.example.container.module1 = new YAHOO.widget.Panel( 'module1', { close:true, draggable:true, constraintoviewport:true } ); YAHOO.example.container.module1.render(); YAHOO.widget.Module.textResizeEvent.subscribe( function(o){ console.log('Text has been resized!') } ); });
This works with one feature of YUI event that is very close to
my heart: Custom Events.
Custom Events allow you to notify an unknown amount of
listeners about what is happening...
... sending information not necessarily accessible to them
when it happens.
Every single YUI component has a lot of Custom Events you
can subscribe to.
Say for example you want to make sure to securely chain
animation sequences...
//This is the first animation; this one will //fire when the button is clicked. var move = new YAHOO.util.Anim("animator", { left: {from:0, to:75} }, 1); //This is the second animation; it will fire //when the first animation is complete. var changeColor = new YAHOO.util.ColorAnim( "animator", { backgroundColor: {from:"#003366", to:"#ff0000"} }, 1); //Here's the chaining glue: We subscribe to the //first animation's onComplete event, and in //our handler we animate the second animation: move.onComplete.subscribe(function() { changeColor.animate(); });
//Here we set up our YUI Button and subcribe to //its click event. When clicked, it will //animate the first animation: var start = new YAHOO.widget.Button("startAnim"); start.subscribe("click", function() { //reset the color value to the start so that //the animation can be run multiple times: YAHOO.util.Dom.setStyle("animator", "backgroundColor", "#003366"); move.animate(); });
//You can also make use of the onStart and onTween //custom events in Animation; here, we'll log all //of changeColor's custom events and peek at their //argument signatures: changeColor.onStart.subscribe(function() { YAHOO.log("changeColor animation is starting.", "info", "example"); }); changeColor.onTween.subscribe(function(s, o) { YAHOO.log("changeColor onTween firing with these arguments: " + YAHOO.lang.dump(o), "info", "example"); }); changeColor.onComplete.subscribe(function(s, o) { YAHOO.log("changeColor onComplete firing with these arguments: " + YAHOO.lang.dump(o), "info", "example"); });
Knowing when something happens and being able to
react to it is much safer than assuming it worked.
Knowledge is power.
This is why 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()!
All YUI components come as a debug version which log
everything that is going on to the logger.
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.
So how is YUI good for professional and easy
development?
Built on agreed standards
Separated into modules each dealing with one task
Constant reporting of what is going on
Own Debugging environment
Here’s another small thing I prepared earlier:
Using Event and Dom I can control the visible part:
function move(e){ y = YAHOO.util.Event.getXY(e); if(y[1] > size){ render(y); } }; function render(y){ var d = YAHOO.util.Dom; var real = y[1] - d.getDocumentScrollTop(); d.setStyle(top,'height',real-size+'px'); d.setStyle(bottom,'top',real+size+'px'); var h = d.getViewportHeight() - real + size; d.setStyle(bottom,'height',h + 'px'); };
http://yuiblog.com/blog/2008/09/30/reading-blinds/
What does the future hold?
YUI3http://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
Christian Heilmann
http://wait-till-i.com | http://scriptingenabled.org
http://twitter.com/codepo8
THANKS!