jQuery Introduction

The purpose of jQuery is to make it much easier to use JavaScript on your website.

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What You Should Already Know

Before you start studying jQuery, you should have a basic knowledge of:

• HTML
• CSS
• JavaScript

If you want to study these subjects first, find the tutorials on our Home page.

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What is jQuery?

jQuery is a lightweight, "write less, do more", JavaScript library.
The purpose of jQuery is to make it much easier to use JavaScript on your website.
jQuery takes a lot of common tasks that require many lines of JavaScript code to accomplish, and wraps them into methods that you can call with a single line of code.
jQuery also simplifies a lot of the complicated things from JavaScript, like AJAX calls and DOM manipulation.
The jQuery library contains the following features:

• HTML/DOM manipulation
• CSS manipulation
• HTML event methods
• Effects and animations
• AJAX
• Utilities

Tip: In addition, jQuery has plugins for almost any task out there.

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Why jQuery?

There are lots of other JavaScript frameworks out there, but jQuery seems to be the most popular, and also the most extendable.
Many of the biggest companies on the Web use jQuery, such as:

• Google
• Microsoft
• IBM
• Netflix

	Will jQuery work in all browsers? The jQuery team knows all about cross-browser issues, and they have written this knowledge into the jQuery library. jQuery will run exactly the same in all major browsers, including Internet Explorer 6!

jQuery Tutorial

"Try it yourself" Examples in Each Chapter

With our online editor, you can edit the code, and click on a button to view the result.

Example

$(document).ready(function(){
  $("p").click(function(){
    $(this).hide();
  });
});

Try it yourself »

Click on the "Try it yourself" button to see how it works.

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jQuery Examples

Learn by examples! At W3Schools you will find a lot of jQuery examples to edit and test yourself.

• jQuery Examples

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jQuery References

At W3Schools you will find a complete reference of all jQuery objects and methods.

• jQuery Reference

jQuery Properties

jQuery Properties

Method	Description
context	Deprecated in version 1.10. Contains the original context passed to jQuery()
jquery	Contains the jQuery version number
jQuery.fx.interval	Change the animation firing rate in milliseconds
jQuery.fx.off	Globally disable/enable all animations
jQuery.support	A collection of properties representing different browser features or bugs (Intended for jQuery's internal use)
length	Contains the number of elements in the jQuery object

jQuery Miscellaneous Methods

jQuery Misc Methods

Method	Description
data()	Attaches data to, or gets data from, selected elements
each()	Execute a function for each matched element
get()	Get the DOM elements matched by the selector
index()	Search for a given element from among the matched elements
$.noConflict()	Release jQuery's control of the $ variable
$.param()	Create a serialized representation of an array or object (can be used as URL query string for AJAX requests)
removeData()	Removes a previously-stored piece of data
size()	Deprecated in version 1.8. Return the number of DOM elements matched by the jQuery selector
toArray()	Retrieve all the DOM elements contained in the jQuery set, as an array

jQuery AJAX Methods

jQuery AJAX Methods

AJAX is the art of exchanging data with a server, and update parts of a web page - without reloading the whole page.
The following table lists all the jQuery AJAX methods:

Method	Description
$.ajax()	Performs an async AJAX request
$.ajaxPrefilter()	Handle custom Ajax options or modify existing options before each request is sent and before they are processed by $.ajax()
$.ajaxSetup()	Sets the default values for future AJAX requests
$.ajaxTransport()	Creates an object that handles the actual transmission of Ajax data
$.get()	Loads data from a server using an AJAX HTTP GET request
$.getJSON()	Loads JSON-encoded data from a server using a HTTP GET request
$.getScript()	Loads (and executes) a JavaScript from a server using an AJAX HTTP GET request
$.param()	Creates a serialized representation of an array or object (can be used as URL query string for AJAX requests)
$.post()	Loads data from a server using an AJAX HTTP POST request
ajaxComplete()	Specifies a function to run when the AJAX request completes
ajaxError()	Specifies a function to run when the AJAX request completes with an error
ajaxSend()	Specifies a function to run before the AJAX request is sent
ajaxStart()	Specifies a function to run when the first AJAX request begins
ajaxStop()	Specifies a function to run when all AJAX requests have completed
ajaxSuccess()	Specifies a function to run when an AJAX request completes successfully
load()	Loads data from a server and puts the returned data into the selected element
serialize()	Encodes a set of form elements as a string for submission
serializeArray()	Encodes a set of form elements as an array of names and values

jQuery Traversing Methods

Query Traversing Methods

Method	Description
add()	Adds elements to the set of matched elements
addBack()	Adds the previous set of elements to the current set
andSelf()	Deprecated in version 1.8. An alias for addBack()
children()	Returns all direct children of the selected element
closest()	Returns the first ancestor of the selected element
contents()	Returns all direct children of the selected element (including text and comment nodes)
each()	Executes a function for each matched element
end()	Ends the most recent filtering operation in the current chain, and return the set of matched elements to its previous state
eq()	Returns an element with a specific index number of the selected elements
filter()	Reduce the set of matched elements to those that match the selector or pass the function's test
find()	Returns descendant elements of the selected element
first()	Returns the first element of the selected elements
has()	Returns all elements that have one or more elements inside of them
is()	Checks the set of matched elements against a selector/element/jQuery object, and return true if at least one of these elements matches the given arguments
last()	Returns the last element of the selected elements
map()	Passes each element in the matched set through a function, producing a new jQuery object containing the return values
next()	Returns the next sibling element of the selected element
nextAll()	Returns all next sibling elements of the selected element
nextUntil()	Returns all next sibling elements between two given arguments
not()	Remove elements from the set of matched elements
offsetParent()	Returns the first positioned parent element
parent()	Returns the direct parent element of the selected element
parents()	Returns all ancestor elements of the selected element
parentsUntil()	Returns all ancestor elements between two given arguments
prev()	Returns the previous sibling element of the selected element
prevAll()	Returns all previous sibling elements of the selected element
prevUntil()	Returns all previous sibling elements between two given arguments
siblings()	Returns all sibling elements of the selected element
slice()	Reduces the set of matched elements to a subset specified by a range of indices

jQuery HTML / CSS Methods

jQuery HTML / CSS Methods

The following table lists all the methods used to manipulate the HTML and CSS.
The methods below work for both HTML and XML documents. Exception: the html() method.

Method	Description
addClass()	Adds one or more class names to selected elements
after()	Inserts content after selected elements
append()	Inserts content at the end of selected elements
appendTo()	Inserts HTML elements at the end of selected elements
attr()	Sets or returns attributes/values of selected elements
before()	Inserts content before selected elements
clone()	Makes a copy of selected elements
css()	Sets or returns one or more style properties for selected elements
detach()	Removes selected elements (keeps data and events)
empty()	Removes all child nodes and content from selected elements
hasClass()	Checks if any of the selected elements have a specified class name
height()	Sets or returns the height of selected elements
html()	Sets or returns the content of selected elements
innerHeight()	Returns the height of an element (includes padding, but not border)
innerWidth()	Returns the width of an element (includes padding, but not border)
insertAfter()	Inserts HTML elements after selected elements
insertBefore()	Inserts HTML elements before selected elements
offset()	Sets or returns the offset coordinates for selected elements (relative to the document)
offsetParent()	Returns the first positioned parent element
outerHeight()	Returns the height of an element (includes padding and border)
outerWidth()	Returns the width of an element (includes padding and border)
position()	Returns the position (relative to the parent element) of an element
prepend()	Inserts content at the beginning of selected elements
prependTo()	Inserts HTML elements at the beginning of selected elements
prop()	Sets or returns properties/values of selected elements
remove()	Removes the selected elements (including data and events)
removeAttr()	Removes one or more attributes from selected elements
removeClass()	Removes one or more classes from selected elements
removeProp()	Removes a property set by the prop() method
replaceAll()	Replaces selected elements with new HTML elements
replaceWith()	Replaces selected elements with new content
scrollLeft()	Sets or returns the horizontal scrollbar position of selected elements
scrollTop()	Sets or returns the vertical scrollbar position of selected elements
text()	Sets or returns the text content of selected elements
toggleClass()	Toggles between adding/removing one or more classes from selected elements
unwrap()	Removes the parent element of the selected elements
val()	Sets or returns the value attribute of the selected elements (for form elements)
width()	Sets or returns the width of selected elements
wrap()	Wraps HTML element(s) around each selected element
wrapAll()	Wraps HTML element(s) around all selected elements
wrapInner()	Wraps HTML element(s) around the content of each selected element