jQuery

JQUERY
Prepared By

Jay Poojara

1

WHAT IS JQUERY?
jQuery is a fast, small, and feature-rich JavaScript library. It
makes things like HTML document traversal and manipulation, event
handling, animation, and Ajax much simpler with an easy-to-use API
that works across a multitude of browsers. With a combination of
versatility and extensibility, jQuery has changed the way that millions of
people write JavaScript.

2

WHY IS JQUERY AWESOME?
What jQuery does well:
1.
2.
3.
4.
5.

Simplified AJAX
DOM Manipulation
Event Management
Animations
Normalizes Browser Differences

Why It Is Successful:
1.
2.
3.
4.
5.

Well Designed
Easy to extend with plugins
Great Documentation
Large jQuery Community
Cross-browser

3

WHO'S USING JQUERY?

….This are some of the examples….

5

JQUERY PHILOSOPHY
Find some stuff

Do something to it

6

SAMPLE JQUERY
Our DOM
Include jQuery
The „ready event‟ – Binds a function to
be executed whenever the DOM is
ready
Select the „toggleContent‟ DOM
element and bind a click event
handler to it.
Select the „content‟ DOM element and
set the text to „Hello World!‟
Prevent the default behavior of the
anchor tag by returning false
7

DOLLAR FUNCTION $();
• JavaScript identifiers can start with $
• The jQuery framework automatically assigns „$‟ to the „jQuery‟
function
$ === jQuery true
$(selector) is same as jQuery(selector)

• Can use utility function to unassign $
$.noConflict();
$ === jQuery;

false

• Can reassign jQuery to another variable
$j = $.noConflict();

$j === jQuery;

true

$j === $;

false
8

$ === jQuery;

false

DOCUMENT READY EVENT
• $(document).ready(fn);
• The bound function will be called the instant the
DOM is ready to be read and manipulated.
• As many as you want on the page.
• Executed in the order they were added.

• There is a shortcut: $(fn);

9

SELECTORS
CSS3 Selectors
jQuery

Selects…

$(„#myId‟)

By ID

$(„div‟)

By Element Type

$(„.myClass‟)

By Class

$(„div, span, p.myClass, #myid‟)

Multiple

$(„*‟)

All

$(„.myClass‟, this), $(„p.myClass‟)

By Context (better performance)

$(„#main div‟)

Descendents (all levels)

$(„#main > div‟)

Children (first level)

$(„label + input‟)

The immediate element after

$(„#prev ~ div‟)

The first element after

$(„div[id]‟)

All elements that have the specified attribute

$(„input[type=text]‟)

By Attribute value
10

FILTERS
$(„div:empty‟), $(„:empty‟), $(„div:not(:empty)‟)
jQuery

Filters…

:first, :last, :nth(n)

First, Last, Nth Element

:odd, :even

Odd, Even Elements

:visible, :hidden

Visible, Hidden Elements

:enabled, :disabled

Enabled, Disabled Elements

:contains(“text”)

Contains specified text

:empty

Elements w/ no children (or text)

:first-child, :last-child, :nthchild(n)

Child Element

:lt(n), :gt(n)

Elements w/ index below or after

:not(selector)

Does not match selector

:MyCustomFilter

Custom Filters (Implement your own!)

Custom Filter Used

11

CHAINING
• Most jQuery methods return another jQuery object (usually the same
collection), which means you can chain method calls together with a
fluent like syntax
• Some methods that stop a chain, these methods return a value from the
jQuery object
.css(name), .text(), .html(), .val(), .height(), .width(), .is(„:visible‟)

• Some methods will return a different jQuery collection, you can revert
to the previous collection by calling .end();

12

ATTRIBUTES & CLASSES
• Getters & Setters for attr, html, text, val
• Getter (returns String – breaks chain)
var text = $(„#myDiv‟).text();

• Setter (returns jQuery)
$(„#myDiv‟).text(„Hello World!‟);

• text() escapes html()
• val() used with inputs

• attr() can take JSON

• Add, Remove for Attributes & Classes
• .removeAttr(„someAttr‟);
• .addClass(„someClass‟);

• .removeClass(„someClass‟);
• .toggleClass(„someClass‟);
13

TRAVERSING
• Family
• parent, parents, siblings, children

• Proximity
• closest, next, prev, nextAll, prevAll

• Searching
• find

14

EVENTS
.bind(type, data, fn)
• Binds a handler to an event on all matched elements

.one(type, data, fn)
• Binds a handler to be executed only once for each matched element

.trigger(event, data)
• Trigger an event to occur on all matched elements

.unbind(type, fn)
• Removes event handlers from all matched elements

.live(type, fn)
• Binds a handler to an event on all currently matched and future matched elements.

.die(type, fn)
• Removes a bound live event.

.hover(fnOver, fnOut)
• Interaction helper that will handle mouseover and mouseout

.toggle(fn1, fn2, fn3, fnN, …)
• Interaction helper that will toggle among two or more function calls every other click.

15

EVENT HELPERS
blur, change, click, dblclick, error, focus, keydown, keypress, k
eyup, load, mousedown, mouseenter, mouseleave, mousemov
e, mouseup, resize, scroll, select, submit, unload

16

MANIPULATION
• Inserting Inside
•

append, prepend

•

appendTo, prependTo

• Inserting Outside
•

after, before

•

insertAfter, insertBefore

• Inserting Around
•

wrapInner

•

wrap

•

wrapAll

• Replacing
•

replaceWith, replaceAll

• Removing
•

empty, remove

• Copying
•

clone
17

EFFECTS
• Basics
• show, hide, toggle

• Sliding
• slideUp, slideDown, slideToggle

• Fading
• fadeIn, fadeOut, fadeTo (opacity 0-1)

• Custom
• animate, stop

18

PLUG-INS
• Extremely Simple – Promotes code reuse and DRY principle
$.fn.MyPlugin = function(params) {};

• Return a jQuery object to prevent from “breaking the chain”
• Unless you are returning a specific value

• Best Practice is to wrap the plug-in declaration within an anonymous
JavaScript function in order to prevent collisions with the use of $

19

UTILITY FUNCTIONS
• Array and Object Operations
$.each(object, callback) – Callback function will run for each item in the object. The each method
is meant to be an immutable iterator and returns the original array.
$.map(array, callback) – Callback function will run for each item in the array. The map method
can be used as an iterator, but is designed to be used for manipulation of the supplied array
and returns a new array.
$.merge(first, second) – Merges the second array into the first array.
$.unique(array) – Removes duplicate elements (only works on arrays of DOM elements).
$.extend(object) – Add functions into the jQuery namespace.
$.extend(deep, target, object1, objectN) – Merge values from objects 1 to N into target object.
Deep is an optional boolean that if true, tells jQuery to do a deep copy.
$.grep(array, callback, invert) – Iterates through array, and returns a new array with values from
the original array that satisfy the criteria specified in the callback.
$.inArray(value, array) – Gets the index of the value in the array (-1 if not found).

• String Operations
$.trim(str) – Removes whitespace from the given string.

• Test Operations
$.isArray(obj) – Determines if the object is an array.
$.isFunction(obj) – Determines if the object is a function.

20

JQUERY DATA
• Can store data on one or more jQuery elements
• .data(name, value)

• value is an object

• Retrieves data from the first element in the jQuery object
• .data(name)

21

RESOURCES
• jQuery Main
•

http://jquery.com

•

http://docs.jquery.com/Downloading_jQuery

• jQuery API Documentation
•

http://api.jquery.com

•

http://docs.jquery.com

• jQuery UI
•

http://jqueryui.com

•

http://jqueryui.com/themeroller/

• jQuery Blog
•

http://blog.jquery.com/

• Around The Web
•

•

http://www.nettuts.com

•

•

http://stackoverflow.com

http://www.smashingmagazine.com

Tools
•

Visual Studio JavaScript Intellisense Support (KB958502)

•

http://getfirebug.com/ (Firebug Firefox Plug-in)

•

http://jsbin.com/ (JS Bin - Collaborative JavaScript Debugging)

22

THANK YOU
Even a correct decision is wrong when it was taken too
late.

any Queries?

23

jQuery

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