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
$.getJSON('b.json');
});

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

Execute a script
$.getScript('c.js');
});

Load other data formats
$.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)

Thanks A Millions
?
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Introduction to jQuery

by manugoel2003 on Sep 12, 2007

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Introduction to jQuery — Presentation Transcript