Introduction to jQuery

jQuery Javascript that doesn't suck! Presented By Mir Nazim www.mirnazim.com [email_address]

WHAT and WHEN John Resig - www.ejohn.org Released at BarCamp NYC on Jan 2006 jQuery 1.0 out on Aug 2006 version 1.1.3 latest ~ 800% faster for DOM processing numerous other improvements

WHY Doesn’t mess with the language (Prototype) Doesn’t try to be Python (Mochikit) Only essentials: > 20 KB (Scriptaculous, Dojo) More than cosmetic effects (Moo.fx) Makes common tasks a breeze

OTHER REASONS Great Documentaions Great community Tons of plugins Works everywhere RELIABLY IE 6+, Firefox, Safari 2+, and Opera 9+

What jQuery Deos GENRAL PURPOSE ABSTRACTION LAYER FOR COMMON WEB SCRIPTING TASKS

What's Good in it Access parts of a page Modify the appearance of a page Alter the content of a page Respond to a user's interaction Add animation to a page Retrieve information (Ajax) Simplify common tasks

How jQuery does it Leverage knowledge of CSS Abstract away browser quirks Always work with sets Allow multiple actions in one line Support extensions

Getting Started <head> <script src="jquery.js" type="text/javascript"> </script> <script type="text/javascript"> $(document).ready(function(){ // your stuff goes here }); </script> </head>

The $() function A factory for jQuery object Provides a jQuery instance All operations are done using $()

Element Selection - CSS $(document).ready(function(){ //select all ”p” elements $(”p”); //select an element with id=”soem-id” $(”#some-id”); //select all elements with class=”soem-class” $(”.some-class”); });

More Element Selection /* select 'li' elements that are children of 'ul' with id=”some-ul” */ $('ul#some-ul > li')

Element Selection - XPath //all links with a title attributes $('a[@title]') //all ”divs” containing on ”ol” element $('div[ol]')

Xpath + RegEx //all links with ”href” starting with ”mailto:” $('a[@href^="mailto:"]') //all links with ”href” ending with ”.pdf” $('a[@href$=".pdf"]') //all links that contain ”mysite.com” anywhere in ”href” $('a[@href*="mysite.com"]')

Custom Selectors //selects 2 nd div from the set $('div.someclass:eq(0)') // same as above but CSS based $('div.someclass:nth-child(1)')

Select Even/Odd Rows of table $('tr:odd') //all odd rows $('tr:even') //all even rows

DOM Traversal Same Effect, Different way $('tr').filter(':odd') //all odd rows $('tr').filter(':even') //all even rows

DOM Traversal //select the parent element of ”th” $('th').parent() //select all even ”tr” but not that contain a ”th” $('tr:not([th]):even') //select all odd ”tr” but not that contain a ”th” $('tr:not([th]):odd')

More DOM $('td:contains("Henry")').siblings() $('td:contains("Henry")').parent().find('td:gt(0)') $('td:contains("Henry")').parent().find('td') .not(':contains("Henry")') ) $('td:contains("Henry")').parent().find('td:eq(1)')

Method Chaining //get every cell containing "Henry" $('td:contains("Henry")') //get its parent .parent() //find inside the parent the 2nd cell .find('td:eq(1)') //add the "highlight" class to that cell .addClass(highlight') //revert back to the parent of the cell containing "Henry" .end() //find inside the parent the 3rd cell .find('td:eq(2)') //add the "highlight" class to that cell .addClass('highlight');

Events $('#some-element').bind('click',function() { $('body').addClass('large'); //some more stuff //even some more stuff }); use event names without on part. E.G onClick => click onKeyPress => keypress

Compound Events // add and remove class on alternate clicks $('#some-element'). toggle (function() { $('#switcher.button').addClass('hidden'); }, function() { $('#switcher.button').removeClass('hidden'); });

One compound event //works like ”:hover” pseudo class $('#some-element').hover(function() { $(this).addClass('hover'); }, function() { $(this).removeClass('hover'); });

Manipulating Attributes //change the ”title” attribute of ”a” element where id=”some-id” $('a#some-id').attr({'title': 'Some Text here'}); //more than one at a time $('a#some-id').attr({ 'title':'Some Text here', 'href':'www.example.com', 'id':'some-other-id', });

Changing the tag content //eq of element.innerHTML() $('#some-div').html() //eq of element.innerHTML = some-var $('#some-div').html(some-var) //eq of some-input.value $('input').val() //eq of some-input.value = some-var $('input').val(some-var)

AJAX /* when a buttong with id=”some-button” is clicked load ”a.html” in div with id=”some-div” */ $('#some-button').click(function() { $('#some-div').load('a.html'); });

AJAX + JSON $('#some-button').click(function() { $.getJSON('b.json'); });

Take action on data $('#some-button').click(function() { $.getJSON('b.json', function(data) { // do some stuff with data you just go });

Execute a script $('#some-button').click(function() { $.getScript('c.js'); });

Load other data formats $('#some-button').click(function() { $.get('my-format.data', function(data) { //handle your data way you want }); });

A GET request $.get('e.php', {'term': $(this).text()}, function(data) { $('#some-div').html(data); } );

POST request $.post('e.php', {'term': $(this).text()}, function(data) { $('#some-div').html(data); } );

AJAX observers $('#loading'). ajaxStart (function() { $(this).show(); }). ajaxStop (function() { $(this).hide(); });

There is more Loads of good quality plugins for Extended AJAX functionality Cool Effects Extensions to core jQuery much more http://jquery.com/plugins http://doc.jquery.com/Plugins

Resources http://doc.jquery.com www.visualjquery.com www.Google.com 15 days of jQuery (blog) Learning jQuery (blog)

Introduction to jQuery

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