Inside jQuery (2011)

Inside jQuery
Kenneth Auchenberg

Inside jQuery @auchenberg kenneth.io

Inside jQuery
Kenneth Auchenberg

Twitter Blog


About me
Bah


Agenda


The basics.

jQuery.

Go Go Go!


The basics


Browsers


BOM vs. DOM?


Document

Location

History

Frames
BOM
Navigator Browser Object Model


HTML
DOM
Document Object Model


SVG DOM
Scalable Vector Graphics

MathML DOM
Mathematical Markup Langugage

SMIL DOM
Synchronized Multimedia Integration Language

DOM
Document Object Model


domReady vs. onLoad?


domReady vs. onLoad?
DOMcontentLoaded vs. onLoad?


Closure Library

Frameworks
Abstractions


“ Looking at how Behaviour works, I've never
been completely happy - it simply seems too
tedious and verbose for everyday ”

John Resig
December 2005
Quote from http://ejohn.org/blog/selectors-in-javascript/


A: Behaviour B: pre-jQuery
  Behaviour.register({ $('#example li').bind('click',function(){
    '#example li': function(e){     this.parentNode.removeChild(this);
      e.onclick = function(){ });
        this.parentNode.removeChild(this);
      }
    }
  });

A: Behaviour.register({'':function(e){e.on=}}); 
B: $('').bind('',);

Syntax


A: Behaviour B: pre-jQuery
  Behaviour.register({ $('#foo ol li')
    '#foo ol li': function(a) {  .set('title','List Items!')
      a.title = "List Items!";  .bind('click',function(){alert('Hello!');})
      a.onclick = function(){alert('Hello!');};     .select('.tmp')
    },       .style('color','white')
    '#foo ol li.tmp': function(a) {       .select('.foo')
      a.style.color = 'white';         .style('background','red');
    },
    '#foo ol li.tmp .foo': function(a) {
      a.style.background = 'red';
    }
  });

A: Behaviour.register({'':function(a){a.=;a.on=;},'#foo ol li':function(a){a.style.='';},
B: $('').set('','').bind('',).select('').style('','').select('').style('','');


jQuery

Prototype

Trend
October 2010
Scale is based on the average worldwide traffic of jquery javascript from 2004 to 2010.
Source: http://www.google.com/trends?q=dojo+javascript,+jquery+javascript,+yui+javascript,+prototype+javascript,+mootools+javascript&ctab=0&geo=all&date=all&sort=1


Prototype

jQuery Usage
October 2010
Distribution is calculated from a cross section of website domains provided by URLs entered at BuiltWith.com and the Quantcast Top Million. Last calculated on October 19 2010.
Source: http://trends.builtwith.com/javascript


$?


var $ = ‘Hello World’;

var € = ‘Hello World’;

var @ = ‘Hello World’;
var _ = ‘Hello World’;
Identiﬁes Names


“
7.6 Identifier Names and Identifiers
Identifier Names are tokens that are interpreted according
to the grammar given in the “Identifiers” section of chapter
5 of the Unicode standard, with some small modifications.
An Identifier is an IdentifierName that is not a
ReservedWord (see 7.6.1). The Unicode identifier
grammar is based on both normative and informative
character categories specified by the Unicode Standard.
The characters in the specified categories in version 3.0
of the Unicode standard must be treated as in those
categories by all conforming ECMAScript
implementations.

This standard specifies specific character additions: The
dollar sign ($) and the underscore (_) are permitted
anywhere in an IdentifierName. ECMA-262
…”

Quote from Standard ECMA-262 ECMAScript Language Specification


Utilities Traversing Attributes Effects

Core Selectors Manipulation CSS Events Ajax

jQuery

jQuery


Selectors & Performance

Events & Delegation

AJAX & Communication

Extensions & Community


Which browsers does
jQuery support?


3.0+

9.0+

2.0+

6.0+
Browsers
1.0+


Getting started


<!DOCTYPE html>
<html>
  <head>
      <title>jQuery</title>
  </head>
 
  <body></body>
 
  <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/
jquery/1.4.3/jquery.min.js"></script>
</html>

Inject

$(document).ready(function() {
     // Go mental
}(;

Ready


jQuery code begins $
followed by a selector
and ends with action(s)
$(’div’).addClass(‘kenneth’);

$(’div.groups‐panel’).addClass(‘kenneth’).find(’span:first‐
child’).text(‘rocks’).show();


Selectors and actions can be attached to
events.
$(’body’).click(function() {
     $(’div’).addClass(‘kenneth’) ;
});

$(’body’).live(’click’, function() {
});


Selectors


document.getElementById('header')

document.getElementsByTagName('p')

document.getElementsByClassName(‘.hey’)

'body > div.wrapper > section'?

Browser selectors


Selector Engine


!"#$ ;<"3-)$ ;+=(),"(->)?$ ;()5G+5"&#$
%&%'%()$ ;&,-)$ ;%'2)B$ ;<"3-)G+5"&#$
*+&,--$ ;(=)>-%&?$ ;5,->-%&?$ ;&,-)G+5"&#$
*+&,--*+&,--$ ;%6%($ ;2,3%()$ ;=(&BG+5"&#$
.$ ;=##$ ;5"##%($
-%&/0$-%&1$ ;%@>"(#%8?$ ;6"-":&%$ ;"(2H)$
;A)>"(#%8?$ ;<"&%$
2,3%()$4$+5"&#$ ;&)>"(#%8?$ .C,))3D$ ;:H))=($
23%6$7$(%8)$ ;5%,#%3$ .C,))3E6,&D$ ;%(,:&%#$
23%6$9$-":$ ;,("',)%#$ .C,))3FE6,&D$ ;+5%+I%#$
.C,))DC,))1D$ ;-%&%+)%#$

Selectors

• 2003.03.25: document.getElementsBySelector() by Simon Willison (later used in behaviour.js)[source]
• 2004.04.10: CssQuery() 1.0: by Dean Edwards
• 2005.08.19: CssQuery() 2.0.
• 2005.08.22: jSelect (precursor to jQuery)
• 2006.01.14: jQuery first release.
• 2006.01.18: Prototype. Initial release of selector engine.
• 2006.04.04: moo.dom (precursor to mootools
• 2006.08.26: jQuery 1.0
• 2006.11.14: Mochikit Selector. (orig. ported from prototype)
• 2007.01.08: jQuery 1.1a ("10-20x faster than 1.0")
• 2007.01.11: DomQuery by Jack Slocum (ExtJS).
• 2007.02.05: dojo.query().
• 2007.03.21: base2.DOM.
• 2007.05.01: Prototype 1.5.1
• 2007.05.07: Mootools 1.1
• 2007.07.01: jQuery 1.1.3 ("800% faster")
• 2007.07.10: Ext 1.1 RC1
•
•
2007.07.10: Dojo 0.9
2007.12.04: YUI 2.4.0
Timeline
• 2007.12.17: NWMatcher by Diego Perini
• 2008.08.25: Sizzle.js by John Resig

Source: http://paulirish.com/2008/javascript-css-selector-engine-timeline/


Sizzle introduction


if ( document.querySelectorAll ) {

(function(){

var oldSizzle = Sizzle, div = document.createElement("div");

div.innerHTML = "";

// Safari can't handle uppercase or unicode characters when

// in quirks mode.

if ( div.querySelectorAll && div.querySelectorAll(".TEST").length === 0 ) {

return;

}

Sizzle = function(query, context, extra, seed){

context = context || document;

// Only use querySelectorAll on non-XML documents

// (ID selectors don't work in non-HTML documents)

if ( !seed && !Sizzle.isXML(context) ) {

if ( context.nodeType === 9 ) {

try {

return makeArray( context.querySelectorAll(query), extra );

} catch(qsaError) {}

querySelectorAll

$(ʻheader aʼ)


$(ʻheader aʼ)

document.querySelectorAll(ʻheader aʼ)

????????

Selector break-down


array = [ʻ.headerʼ , ʻaʼ]


Left to right Right to left

MooTools Sizzle

Ext.JS YUI 3

Prototype.js querySelectorAll

Direction


match: {
     ID: /#((?:[wu00c0‐uFFFF‐]|.)+)/,
     CLASS: /.((?:[wu00c0‐uFFFF‐]|.)+)/,
     NAME: /[name=['"]*((?:[wu00c0‐uFFFF‐]|.)+)['"]*]/,
     ATTR: /[s*((?:[wu00c0‐uFFFF‐]|.)+)s*(?:(S?=)s*(['"]*)(.*?)3|)s*]/,
     TAG: /^((?:[wu00c0‐uFFFF*‐]|.)+)/,
     CHILD: /:(only|nth|last|first)‐child(?:((even|odd|[dn+‐]*)))?/,
     POS: /:(nth|eq|gt|lt|first|last|even|odd)(?:((d*)))?(?=[^‐]|$)/,
     PSEUDO: /:((?:[wu00c0‐uFFFF‐]|.)+)(?:((['"]?)((?:([^)]+)|[^()]*)+)2))?/
},

.ﬁnd(ʻaʼ)


TAG: function(match, context){
     return context.getElementsByTagName(match[1]);
}

.ﬁnd(ʻaʼ)


CLASS: function(match, curLoop, inplace, result, not, isXML){
      match = " " + match[1].replace(//g, "") + " ";

      if ( isXML ) {
        return match;
      }

      for ( var i = 0, elem; (elem = curLoop[i]) != null; i++ ) {
        if ( elem ) {
          if ( not ^ (elem.className && (" " + elem.className + " ").replace(/[tn]/g, " 
").indexOf(match) >= 0) ) {
            if ( !inplace ) {
              result.push( elem );
            }
          } else if ( inplace ) {
            curLoop[i] = false;
          }
        }
      }

 
 
 
 
 
},
return false;
.ﬁnd(ʻ.headerʼ)


$(ʻdiv.me .projectsʼ)

$(ʻ.me div.projectsʼ)

http://jsperf.com/sizzle-selector-performance


Performance


cache vs. no-cache

http://jsperf.com/cache-jquery-objects


jQuery.each vs. for loop

http://jsperf.com/jquery-each-vs-for-loop/11


jQuery.trim vs. RegExp

http://jsperf.com/jquery-trim-vs-regexp-trim


http://jsperf.com/jquery-htmlencode-vs-string-replace/3


jQuery vs. HtmlEncode

http://jsperf.com/jquery-htmlencode-vs-string-replace/3


(build) string vs. object

http://jsperf.com/build-appended-object-test/3


Events and delegation


.bind(eventname, function)        .click, .hover, .mouseover
.unbind(eventname)                       .focus, .submit
.trigger(eventname, function)

.live(eventname, function)
.delegate(eventname, function)

$(’body’).click(function() {
$(’div’).addClass(’zyb’) ;
});
Events


$(’body’).click(function() {
});

$(’body’).live(‘click’, function() {
});

$(’body’).delegate(‘div’, ‘click’, function() {
}); Event delegation


Event delegation


<ul class="myList">
<li class="red">The first item.</li>
<li class="green">The second item.</li>
<li class="yellow">The third item.</li>
<li class="blue">The fourth item.</li>
</ul>
Class of the last clicked item: 

$(’ul’).click(function(event) {
if(event.target.nodeName == ”LI”) {
$(’#display’).text(event.target.className);
}
});

How does it work?

<ul class="myList">
<li class="red">The first item.</li>

<li class="green">The second item.</li>
<li class="yellow">The third item.</li>

<li class="blue">The fourth item.</li>
</ul>

Class of the last clicked item: 
$("ul").click( function( event ) {
var elem = event.target;
while( elem.nodeName != "LI" && elem.parentNode) {
elem = elem.parentNode;
}
if(elem.nodeName == "LI") {
$("#display").text(event.target.className);
}
What if inside?
});

<ul class="myList">
  <li class="red">The first item.</li>
 
  <li class="green">The second item.</li>
  <li class="yellow">The third item.</li>
 
  <li class="blue">The fourth item.</li>
</ul>
 
Class of the last clicked item: <span id="display"> 

$("ul").click( function( event ) {
  var $elem = $(event.target).closest("li");
  if($elem.length) {
    $("#display").text($elem.attr("class"));
  }
});
Closest to the
rescue

<ul class="myList">
  <li class="red">The first item.</li>
 
  <li class="green">The second item.</li>
  <li class="yellow">The third item.</li>
 
  <li class="blue">The fourth item.</li>
</ul>
 
Class of the last clicked item: <span id="display"> 

$("ul.myList > li").live("click", function(e) {
  $("#display").text(
    $(this).attr("class")
  );
});

$("ul").delegate("li", "click", function(e) {
  $("#display").text(
.live & .delegate
    $(this).attr("class")
  );
});

EventHelper = (function (window, $, undefined) {

  function proxy_callback(callback, shouldPreserveDefault, e) {
    var target = $(e.currentTarget);
    if (!shouldPreserveDefault) {
      e.preventDefault();
    }
    callback.apply(this, 
[target].concat(Array.prototype.slice.call(arguments).slice(2)));
  }

  function bind(eventType, selector, fn, shouldPreserveDefault) {
    $('body').delegate(selector, eventType, proxy_callback.curry(fn, 
shouldPreserveDefault));
  }

  function unbind(eventType, selector) {
    $('body').undelegate(selector, eventType);
  } Wrappers
})(window, jQuery);


AJAX/Communication


.ajax(options)

.get(url, data, callback, dateType)
.post(url, data, callback, dateType)
.getJSON(url, data, callback, dateType)
.getScript(url, callback)

.load(url, data, callback)

.ajaxComplete()              .ajaxSetup(options)
.ajaxStart()
.ajaxStop()
.ajaxSuccess()
.ajaxError()
Ajax in jQuery


CORS


CORS
Cross-Origin Resource Sharing


Header


Access-Control-Allow-Origin: *
Header


$.get(“http://bar.other/resources/public‐data”, function() {
    console.log(arguments);
}, “xml”)
GET /resources/public-data/ HTTP/1.1
Host: bar.other
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b3pre) Gecko/20081130 Minefield/
3.1b3pre
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer: http://foo.example/examples/access-control/simpleXSInvocation.html
Origin: http://foo.example

HTTP/1.1 200 OK
Date: Mon, 01 Dec 2008 00:23:53 GMT
Server: Apache/2.0.61
Access-Control-Allow-Origin: *
Keep-Alive: timeout=2, max=100
Connection: Keep-Alive
Transfer-Encoding: chunked
Content-Type: application/xml

[XML Data]


callback=?


TwitterAPI = function() {

function getUserData(username) {

$.getJSON('http://twitter.com/status/user_timeline/' + username + '.json?count=10&callback=?', onSucesss);

}

function onSuccess(responseData) {

// to render

}

return {

getUserData: getUserData

}

}();

TwitterAPI.getUserData('auchenberg');

JSONP
JSON with Padding


Demo time


function poll(callback){
        $.ajax({
            type: "GET",
            url: ”http://localhost:8080/cometd",
            timeout:50000,

            success: function(data){
                callback(data);
            },
            error: function(XMLHttpRequest, textStatus, errorThrown){
                // Do the logging
                
            }
        });
    };

   setInterval(poll(onPollFinished)), 2000);

XHR Polling
Old


Chat server
(socket.io)

XHR Long-polling XHR Multipart WebSockets

IE Firefox Chrome

Real time


function longPool(callback){
        $.ajax({
            type: "GET",
            url: ”http://localhost:8080/cometd",
            timeout:50000,

            success: function(data){
                callback(data);
         longPool(callback);
            },
            error: function(XMLHttpRequest, textStatus, errorThrown){
                // Do the logging
                longPool(callback);
            }
        });
    };

XHR Long Polling
HTTP 1.1


MIME‐Version: 1.0 HTTP/1.1 200 OK 

Content‐Type: multipart/mixed; boundary="frontier" Content‐Type: text/plain 
Transfer‐Encoding: chunked
This is a message with multiple parts in MIME format.  
‐‐frontier 25 
Content‐Type: text/plain This is the data in the first chunk
 
This is the body of the message. 1C 
‐‐frontier and this is the second one
Content‐Type: application/octet‐stream  
Content‐Transfer‐Encoding: base64 0 

PGh0bWw+CiAgPGhlYWQ+CiAgPC9oZ

XHR Multipart
MIME


Extend


plugins.jquery.com

community


jquery.barcode
Bloat


});

function handler(event) {
    var orgEvent = event || window.event, args = [].slice.call( arguments, 1 ), delta = 0, returnValue = true, deltaX = 0, deltaY = 0;
    event = $.event.fix(orgEvent);
    event.type = "mousewheel";

    // Old school scrollwheel delta
    if ( event.wheelDelta ) { delta = event.wheelDelta/120; }
    if ( event.detail ) { delta = -event.detail/3; }

    // New school multidimensional scroll (touchpads) deltas
    deltaY = delta;

    // Gecko
    if ( orgEvent.axis !== undefined && orgEvent.axis === orgEvent.HORIZONTAL_AXIS ) {
        deltaY = 0;
        deltaX = -1*delta;
    }

    // Webkit
    if ( orgEvent.wheelDeltaY !== undefined ) { deltaY = orgEvent.wheelDeltaY/120; }
    if ( orgEvent.wheelDeltaX !== undefined ) { deltaX = -1*orgEvent.wheelDeltaX/120; }

    // Add event and delta to the front of the arguments
    args.unshift(event, delta, deltaX, deltaY);

    return $.event.handle.apply(this, args);
}

})(jQuery);

jquery.mouseWheel
Custom events

http://github.com/brandonaaron/jquery-mousewheel


var person = {};

$("form").link(person);
$("#name").val("foo");

alert(person.name); // foo
// ... user changes value ...

alert(person.name); // <user typed value>
$(person).data("name", "bar");
alert($("#name").val()); // bar

jquery.dataLink
Databinding

http://github.com/jquery/jquery-datalink

Go Go Go!


Be the cool kid


Thanks


Inside jQuery (2011)

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