$()

$(selector, [context]) ⇒ collection
$(<Zepto collection>) ⇒ same collection
$(<DOM nodes>) ⇒ collection
$(htmlString) ⇒ collection
$(htmlString, attributes) ⇒ collection [v1.0]
Zepto(function($){ ... })

Create a Zepto collection object by performing a CSS selector, wrapping DOM nodes, or creating elements from an HTML string.

A Zepto collection is an array-like object that has chainable methods for manipulating the DOM nodes it references. All of the methods in this documentation are collection methods, except the ones directly on the dollar (Zepto) object, such as $.extend.

If a context (CSS selector, DOM node or Zepto collection object) is given, perform the CSS selector only within nodes of the context; this is functionally the same as calling $(context).find(selector).

When an HTML string is given, use it to create DOM nodes. If an attributes map is given via argument, apply them to all created elements. For fast single element creation, use <div> or <div/> forms.

When a function is given, attach it as a handler for the DOMContentLoaded event. If the page is already loaded, executes the function immediately.

$('div')  //=> all DIV elements on the page
$('#foo') //=> element with ID "foo"
// create element:
$("<p>Hello</p>") //=> the new P element
// create element with attributes:
$("<p />", { text:"Hello", id:"greeting", css:{color:'darkblue'} })
//=> <p id=greeting style="color:darkblue">Hello</p>
// execute callback when the page is ready:
Zepto(function($){
  alert('Ready to Zepto!')
})

jQuery CSS extensions are not supported. However, the optional "selector" module provides limited support for a few of the most used pseudo-selectors, and can be dropped in for compatibility with existing code or plugins.

Zepto will only set the $ global to itself if it is not yet defined. This allows you to use Zepto with legacy code that uses, for example, Prototype.js. Just load Prototype first, and Zepto will not touch Prototype's $ function. Zepto will always set the Zepto global to itself.

$.camelCase v1.0+

$.camelCase(string) ⇒ string

Turn a dasherized string into “camel case”. Doesn’t affect already camel-cased strings.

$.camelCase('hello-there') //=> "helloThere"
$.camelCase('helloThere')  //=> "helloThere"

$.contains v1.0+

$.contains(parent, node) ⇒ boolean

Check if the parent node contains the given DOM node. Returns false if both are the same node.

$.each

$.each(collection, function(index, item){ ... }) ⇒ collection

Iterate over array elements or object key-value pairs. Returning false from the iterator function stops the iteration.

$.each(['a', 'b', 'c'], function(index, item){
  console.log('item %d is: %s', index, item)
})
var hash = { name: '../../../../zepto.js', size: 'micro' }
$.each(hash, function(key, value){
  console.log('%s: %s', key, value)
})

$.extend

$.extend(target, [source, [source2, ...]]) ⇒ target
$.extend(true, target, [source, ...]) ⇒ target [v1.0]

Extend target object with properties from each of the source objects, overriding the properties on target.

By default, copying is shallow. An optional true for the first argument triggers deep (recursive) copying.

var target = { one: 'patridge' },
    source = { two: 'turtle doves' }
$.extend(target, source)
//=> { one: 'patridge',
//     two: 'turtle doves' }

$.fn

Zepto.fn is an object that holds all of the methods that are available on Zepto collections, such as addClass(), attr(), and other. Adding a function to this object makes that method available on every Zepto collection.

Here’s an example implementation of Zepto’s empty() method:

$.fn.empty = function(){
  return this.each(function(){ this.innerHTML = '' })
}

$.grep v1.0+

$.grep(items, function(item){ ... }) ⇒ array

Get a new array containing only the items for which the callback function returned true.

$.inArray v1.0+

$.inArray(element, array, [fromIndex]) ⇒ number

Get the position of element inside an array, or -1 if not found.

$.isArray

$.isArray(object) ⇒ boolean

True if the object is an array.

$.isFunction

$.isFunction(object) ⇒ boolean

True if the object is a function.

$.isPlainObject v1.0+

$.isPlainObject(object) ⇒ boolean

True if the object is a “plain” JavaScript object, which is only true for object literals and objects created with new Object.

$.isPlainObject({})         // => true
$.isPlainObject(new Object) // => true
$.isPlainObject(new Date)   // => false
$.isPlainObject(window)     // => false

$.isWindow v1.0+

$.isWindow(object) ⇒ boolean

True if the object is a window object. This is useful for iframes where each one has its own window, and where these objects fail the regular obj === window check.

$.map

$.map(collection, function(item, index){ ... }) ⇒ collection

Iterate through elements of collection and return all results of running the iterator function, with null and undefined values filtered out.

$.parseJSON v1.0+

$.parseJSON(string) ⇒ object

Alias for the native JSON.parse method.

$.trim v1.0+

$.trim(string) ⇒ string

Remove whitespace from beginning and end of a string; just like String.prototype.trim().

$.type v1.0+

$.type(object) ⇒ string

Get string type of an object. Possible types are: null undefined boolean number string function array date regexp object error.

For other objects it will simply report “object”. To find out if an object is a plain JavaScript object, use isPlainObject.

add

add(selector, [context]) ⇒ self

Modify the current collection by adding the results of performing the CSS selector on the whole document, or, if context is given, just inside context elements.

addClass

addClass(name) ⇒ self
addClass(function(index, oldClassName){ ... }) ⇒ self

Add class name to each of the elements in the collection. Multiple class names can be given in a space-separated string.

after

after(content) ⇒ self

Add content to the DOM after each elements in the collection. The content can be an HTML string, a DOM node or an array of nodes.

$('form label').after('<p>A note below the label</p>')

append

append(content) ⇒ self

Append content to the DOM inside each individual element in the collection. The content can be an HTML string, a DOM node or an array of nodes.

$('ul').append('<li>new list item</li>')

appendTo

appendTo(target) ⇒ self

Append elements from the current collection to the target element. This is like append, but with reversed operands.

$('<li>new list item</li>').appendTo('ul')

attr

attr(name) ⇒ string
attr(name, value) ⇒ self
attr(name, function(index, oldValue){ ... }) ⇒ self
attr({ name: value, name2: value2, ... }) ⇒ self

Read or set DOM attributes. When no value is given, reads specified attribute from the first element in the collection. When value is given, sets the attribute to that value on each element in the collection. When value is null, the attribute is removed (like with removeAttr). Multiple attributes can be set by passing an object with name-value pairs.

To read DOM properties such as checked or selected, use prop.

var form = $('form')
form.attr('action')             //=> read value
form.attr('action', '/create')  //=> set value
form.attr('action', null)       //=> remove attribute
// multiple attributes:
form.attr({
  action: '/create',
  method: 'post'
})

before

before(content) ⇒ self

Add content to the DOM before each element in the collection. The content can be an HTML string, a DOM node or an array of nodes.

$('table').before('<p>See the following table:</p>')

children

children([selector]) ⇒ collection

Get immediate children of each element in the current collection. If selector is given, filter the results to only include ones matching the CSS selector.

$('ol').children('*:nth-child(2n)')
//=> every other list item from every ordered list

clone v1.0+

clone() ⇒ collection

Duplicate all elements in the collection via deep clone.

This method doesn't have an option for copying data and event handlers over to the new elements, as it has in jQuery.

closest

closest(selector, [context]) ⇒ collection
closest(collection) ⇒ collection [v1.0]
closest(element) ⇒ collection [v1.0]

Traverse upwards from the current element to find the first element that matches the selector. If context node is given, consider only elements that are its descendants. This method is similar to parents(selector), but it only returns the first ancestor matched.

If a Zepto collection or element is given, the resulting element will have to match one of the given elements instead of a selector.

var input = $('input[type=text]')
input.closest('form')

concat

concat(nodes, [node2, ...]) ⇒ self

Modify the collection by adding elements to it. If any of the arguments is an array, its elements are merged into the current collection.

This is a Zepto-provided method that is not part of the jQuery API.

contents v1.0+

contents() ⇒ collection

Get the children of each element in the collection, including text and comment nodes.

css

css(property) ⇒ value
css(property, value) ⇒ self
css({ property: value, property2: value2, ... }) ⇒ self

Read or set CSS properties on DOM elements. When no value is given, returns the CSS property from the first element in the collection. When a value is given, sets the property to that value on each element of the collection. Multiple properties can be set by passing an object to the method.

When a value for a property is blank (empty string, null, or undefined), that property is removed. When a unitless number value is given, “px” is appended to it for properties that require units.

var elem = $('h1')
elem.css('background-color')          // read property
elem.css('background-color', '#369')  // set property
elem.css('background-color', '')      // remove property
// set multiple properties:
elem.css({ backgroundColor: '#8EE', fontSize: 28 })

data

data(name) ⇒ value
data(name, value) ⇒ self

Read or write data-* DOM attributes. Behaves like attr, but prepends data- to the attribute name.

When reading attribute values, the following conversions apply: v1.0+

• “true”, “false”, and “null” are converted to corresponding types;
• number values are converted to actual numeric types;
• JSON values are parsed, if it’s valid JSON;
• everything else is returned as string.

Zepto's basic implementation of `data()` only stores strings. To store arbitrary objects, include the optional "data" module in your custom build of Zepto.

each

each(function(index, item){ ... }) ⇒ self

Iterate through every element of the collection. Inside the iterator function, this keyword refers to the current item (also passed as the second argument to the function). If the iterator function returns false, iteration stops.

$('form input').each(function(index){
  console.log('input %d is: %o', index, this)
})

empty

empty() ⇒ self

Clear DOM contents of each element in the collection.

eq

eq(index) ⇒ collection

Get the item at position specified by index from the current collection.

$('li').eq(0)   //=> only the first list item
$('li').eq(-1)  //=> only the last list item

filter

filter(selector) ⇒ collection
filter(function(index){ ... }) ⇒ collection [v1.0]

Filter the collection to contain only items that match the CSS selector. If a function is given, return only elements for which the function returns a truthy value. Inside the function, the this keyword refers to the current element.

For the opposite, see not.

find

find(selector) ⇒ collection
find(collection) ⇒ collection [v1.0]
find(element) ⇒ collection [v1.0]

Find elements that match CSS selector executed in scope of nodes in the current collection.

If a Zepto collection or element is given, filter those elements down to only ones that are descendants of element in the current collection.

var form = $('#myform')
form.find('input, select')

first

first() ⇒ collection

Get the first element of the current collection.

$('form').first()

forEach

forEach(function(item, index, array){ ... }, [context])

Iterate through every element of the collection. Similar to each, but the arguments for the iterator functions are different, and returning false from the iterator won’t stop the iteration.

This is a Zepto-provided method that is not part of the jQuery API.

get

get() ⇒ array
get(index) ⇒ DOM node

Get all elements or a single element from the current collection. When no index is given, returns all elements in an ordinary array. When index is specified, return only the element at that position. This is different than eq in the way that the returned node is not wrapped in a Zepto collection.

var elements = $('h2')
elements.get()   //=> get all headings as an array
elements.get(0)  //=> get first heading node

has v1.0+

has(selector) ⇒ collection
has(node) ⇒ collection

Filter the current collection to include only elements that have any number of descendants that match a selector, or that contain a specific DOM node.

$('ol > li').has('a[href]')
//=> get only LI elements that contain links

hasClass

hasClass(name) ⇒ boolean

Check if any elements in the collection have the specified class.

height

height() ⇒ number
height(value) ⇒ self
height(function(index, oldHeight){ ... }) ⇒ self

Get the height of the first element in the collection; or set the height of all elements in the collection.

$('#foo').height()   // => 123
$(window).height()   // => 838 (viewport height)
$(document).height() // => 22302

hide

hide() ⇒ self

Hide elements in this collection by setting their display CSS property to none.

html

html() ⇒ string
html(content) ⇒ self
html(function(index, oldHtml){ ... }) ⇒ self

Get or set HTML contents of elements in the collection. When no content given, returns innerHTML of the first element. When content is given, use it to replace contents of each element. Content can be any of the types described in append.

// autolink everything that looks like a Twitter username
$('.comment p').html(function(idx, oldHtml){
  return oldHtml.replace(/(^|\W)@(\w{1,15})/g,
    '$1@<a href="http://twitter.com/$2">$2</a>')
})

index

index([element]) ⇒ number

Get the position of an element. When no element is given, returns position of the current element among its siblings. When an element is given, returns its position in the current collection. Returns -1 if not found.

$('li:nth-child(2)').index()  //=> 1

indexOf

indexOf(element, [fromIndex]) ⇒ number

Get the position of an element in the current collection. If fromIndex number is given, search only from that position onwards. Returns the 0-based position when found and -1 if not found. Use of index is recommended over this method.

This is a Zepto-provided method that is not part of the jQuery API.

insertAfter

insertAfter(target) ⇒ self

Insert elements from the current collection after the target element in the DOM. This is like after, but with reversed operands.

$('<p>Emphasis mine.</p>').insertAfter('blockquote')

insertBefore

insertBefore(target) ⇒ self

Insert elements from the current collection before each of the target elements in the DOM. This is like before, but with reversed operands.

$('<p>See the following table:</p>').insertBefore('table')

is

is(selector) ⇒ boolean

Check if the first element of the current collection matches the CSS selector. For basic support of jQuery’s non-standard pseudo-selectors such as :visible, include the optional “selector” module.

jQuery CSS extensions are not supported. The optional "selector" module only provides limited support for few of the most used ones.

last

last() ⇒ collection

Get the last element of the current collection.

$('li').last()

map

map(function(index, item){ ... }) ⇒ collection

Iterate through all elements and collect the return values of the iterator function. Inside the iterator function, this keyword refers to the current item (also passed as the second argument to the function).

Returns a collection of results of iterator function, with null and undefined values filtered out.

// get text contents of all elements in collection
elements.map(function(){ return $(this).text() }).get().join(', ')

next

next() ⇒ collection
next(selector) ⇒ collection [v1.0]

Get the next sibling—optinally filtered by selector—of each element in the collection.

$('dl dt').next()   //=> the DD elements

not

not(selector) ⇒ collection
not(collection) ⇒ collection
not(function(index){ ... }) ⇒ collection

Filter the current collection to get a new collection of elements that don’t match the CSS selector. If another collection is given instead of selector, return only elements not present in it. If a function is given, return only elements for which the function returns a falsy value. Inside the function, the this keyword refers to the current element.

For the opposite, see filter.

offset

offset() ⇒ object
offset(coordinates) ⇒ self [v1.0]
offset(function(index, oldOffset){ ... }) ⇒ self [v1.0]

Get position of the element in the document. Returns an object with properties: top, left, width and height.

When given an object with properties left and top, use those values to position each element in the collection relative to the document.

offsetParent v1.0+

offsetParent() ⇒ collection

Find the first ancestor element that is positioned, meaning its CSS position value is “relative”, “absolute” or “fixed”.

parent

parent([selector]) ⇒ collection

Get immediate parents of each element in the collection. If CSS selector is given, filter results to include only ones matching the selector.

parents

parents([selector]) ⇒ collection

Get all ancestors of each element in the collection. If CSS selector is given, filter results to include only ones matching the selector.

To get only immediate parents, use parent. To only get the first ancestor that matches the selector, use closest.

$('h1').parents()   //=> [<div#container>, <body>, <html>]

pluck

pluck(property) ⇒ array

Get values from a named property of each element in the collection, with null and undefined values filtered out.

$('body > *').pluck('nodeName') // => ["DIV", "SCRIPT"]
// implementation of Zepto's `next` method
$.fn.next = function(){ 
  return $(this.pluck('nextElementSibling')) 
}

This is a Zepto-provided method that is not part of the jQuery API.

position v1.0+

position() ⇒ object

Get the position of the first element in the collection, relative to the offsetParent. This information is useful when absolutely positioning an element to appear aligned with another.

Returns an object with properties: top, left.

var pos = element.position()
// position a tooltip relative to the element
$('#tooltip').css({
  position: 'absolute',
  top: pos.top - 30,
  left: pos.left
})

prepend

prepend(content) ⇒ self

Prepend content to the DOM inside each element in the collection. The content can be an HTML string, a DOM node or an array of nodes.

$('ul').prepend('<li>first list item</li>')

prependTo

prependTo(target) ⇒ self

Prepend elements of the current collection inside each of the target elements. This is like prepend, only with reversed operands.

$('<li>first list item</li>').prependTo('ul')

prev

prev() ⇒ collection
prev(selector) ⇒ collection [v1.0]

Get the previous sibling—optionally filtered by selector—of each element in the collection.

prop v1.0+

prop(name) ⇒ value
prop(name, value) ⇒ self
prop(name, function(index, oldValue){ ... }) ⇒ self

Read or set properties of DOM elements. This should be preferred over attr in case of reading values of properties that change with user interaction over time, such as checked and selected.

push

push(element, [element2, ...]) ⇒ self

Add elements to the end of the current collection.

This is a Zepto-provided method that is not part of the jQuery API.

ready

ready(function($){ ... }) ⇒ self

Attach an event handler for the “DOMContentLoaded” event that fires when the DOM on the page is ready. It’s recommended to use the $() function instead of this method.

reduce

reduce(function(memo, item, index, array){ ... }, [initial]) ⇒ value

Identical to Array.reduce that iterates over current collection.

This is a Zepto-provided method that is not part of the jQuery API.

remove

remove() ⇒ self

Remove elements in the current collection from their parent nodes, effectively detaching them from the DOM.

removeAttr

removeAttr(name) ⇒ self

Remove the specified attribute from all elements in the collection.

removeClass

removeClass([name]) ⇒ self
removeClass(function(index, oldClassName){ ... }) ⇒ self

Remove the specified class name from all elements in the collection. When the class name isn’t given, remove all class names. Multiple class names can be given in a space-separated string.

replaceWith

replaceWith(content) ⇒ self

Replace each element in the collection—both its contents and the element itself—with the new content. Content can be of any type described in before.

scrollTop v1.0+

scrollTop() ⇒ number

Gets the value of how many pixels were scrolled so far on window or scrollable element on the page.

show

show() ⇒ self

Restore the default value for the “display” property of each element in the array, effectively showing them if they were hidden with hide.

siblings

siblings([selector]) ⇒ collection

Get all sibling nodes of each element in the collection. If CSS selector is specified, filter the results to contain only elements that match the selector.

size

size() ⇒ number

Get the number of elements in this collection.

slice

slice(start, [end]) ⇒ array

Extract the subset of this array, starting at start index. If end is specified, extract up to but not including end index.

text

text() ⇒ string
text(content) ⇒ self

Get or set the text content of elements in the collection. When no content is given, returns the text content of the first element in the collection. When content is given, uses it to replace the text contents of each element in the collection. This is similar to html, with the exception it can’t be used for getting or setting HTML.

toggle

toggle([setting]) ⇒ self

Toggle between showing and hiding each of the elements, based on whether the first element is visible or not. If setting is present, this method behaves like show if setting is truthy or hide otherwise.

var input = $('input[type=text]')
$('#too_long').toggle(input.val().length > 140)

toggleClass

toggleClass(names, [setting]) ⇒ self
toggleClass(function(index, oldClassNames){ ... }, [setting]) ⇒ self

Toggle given class names (space-separated) in each element in the collection. The class name is removed if present on an element; otherwise it’s added. If setting is present, this method behaves like addClass if setting is truthy or removeClass otherwise.

unwrap

unwrap() ⇒ self

Remove immediate parent nodes of each element in the collection and put their children in their place. Basically, this method removes one level of ancestry while keeping current elements in the DOM.

$(document.body).append('<div id=wrapper><p>Content</p></div>')
$('#wrapper p').unwrap().parents()  //=> [<body>, <html>]

val

val() ⇒ string
val(value) ⇒ self
val(function(index, oldValue){ ... }) ⇒ self

Get or set the value of form controls. When no value is given, return the value of the first element. For <select multiple>, an array of values is returend. When a value is given, set all elements to this value.

width

width() ⇒ number
width(value) ⇒ self
width(function(index, oldWidth){ ... }) ⇒ self

Get the width of the first element in the collection; or set the width of all elements in the collection.

$('#foo').width()   // => 123
$(window).width()   // => 768 (viewport width)
$(document).width() // => 768 

wrap

wrap(structure) ⇒ self
wrap(function(index){ ... }) ⇒ self [v1.0]

Wrap each element of the collection separately in a DOM structure. Structure can be a single element or several nested elements, and can be passed in as a HTML string or DOM node, or as a function that is called for each element and returns one of the first two types.

Keep in mind that wrapping works best when operating on nodes that are part of the DOM. When calling wrap() on a new element and then inserting the result in the document, the element will lose the wrapping.

// wrap each button in a separate span:
$('.buttons a').wrap('<span>')
// wrap each code block in a div and pre:
$('code').wrap('<div class=highlight><pre /></div>')
// wrap all form inputs in a span with classname
// corresponding to input type:
$('input').wrap(function(index){
  return '<span class=' + this.type + 'field />'
})
//=> <span class=textfield><input type=text /></span>,
//   <span class=searchfield><input type=search /></span>
// WARNING: will not work as expected!
$('<em>broken</em>').wrap('<li>').appendTo(document.body)
// do this instead:
$('<em>better</em>').appendTo(document.body).wrap('<li>')

wrapAll

wrapAll(structure) ⇒ self

Wrap all elements in a single structure. Structure can be a single element or several nested elements, and can be passed in as a HTML string or DOM node.

// wrap all buttons in a single div:
$('a.button').wrapAll('<div id=buttons />')

wrapInner

wrapInner(structure) ⇒ self
wrapInner(function(index){ ... }) ⇒ self [v1.0]

Wrap the contents of each element separately in a structure. Structure can be a single element or several nested elements, and can be passed in as a HTML string or DOM node, or as a function that is called for each element and returns one of the first two types.

// wrap the contents of each navigation link in a span:
$('nav a').wrapInner('<span>')
// wrap the contents of each list item in a paragraph and emphasis:
$('ol li').wrapInner('<p><em /></p>')

Detect module

The “detect” module is useful to fine-tune your site or app to different environments, and helps you to discern between phone and tablets; as well as different browser engines and operating system versions.

// The following boolean flags are set to true if they apply,
// if not they're either set to `false` or `undefined`.
// We recommend accessing them with `!!` prefixed to coerce to a boolean. 
// general device type
$.os.phone
$.os.tablet
// specific OS
$.os.ios
$.os.android
$.os.webos
$.os.blackberry
$.os.bb10
$.os.rimtabletos
// specific device type
$.os.iphone
$.os.ipad
$.os.touchpad
$.os.kindle
// specific browser
$.browser.chrome
$.browser.firefox
$.browser.silk
$.browser.playbook
// Additionally, version information is available as well.
// Here's what's returned for an iPhone running iOS 6.1.
!!$.os.phone         // => true
!!$.os.iphone        // => true
!!$.os.ios           // => true
!!$.os.version       // => "6.1"
!!$.browser.version  // => "536.26"

$.Event

$.Event(type, [properties]) ⇒ event

Create and initialize a DOM event of the specified type. If a properties object is given, use it to extend the new event object. The event is configured to bubble by default; this can be turned off by setting the bubbles property to false.

An event initialized with this function can be triggered with trigger.

$.Event('mylib:change', { bubbles: false })

$.proxy v1.0+

$.proxy(fn, context) ⇒ function
$.proxy(context, property) ⇒ function

Get a function that ensures that the value of this in the original function refers to the context object. In the second form, the original function is read from the specific property of the context object.

var obj = {name: 'Zepto'},
    handler = function(){ console.log("hello from + ", this.name) }
// ensures that the handler will be executed in the context of `obj`:
$(document).on('click', $.proxy(handler, obj))

bind 🐶🔫

Deprecated, use on instead.

bind(type, function(e){ ... }) ⇒ self
bind({ type: handler, type2: handler2, ... }) ⇒ self

Attach an event handler to elements.

delegate 🐶🔫

Deprecated, use on instead.

delegate(selector, type, function(e){ ... }) ⇒ self
delegate(selector, { type: handler, type2: handler2, ... }) ⇒ self

Attach an event handler that is only triggered when the event originated from a node that matches a selector.

die 🐶🔫

Deprecated, use off instead.

die(type, function(e){ ... }) ⇒ self
die({ type: handler, type2: handler2, ... }) ⇒ self

Detach event handler added by live.

live 🐶🔫

Deprecated, use on instead.

live(type, function(e){ ... }) ⇒ self
live({ type: handler, type2: handler2, ... }) ⇒ self

Like delegate where the selector is taken from the current collection.

off

off(type, [selector], function(e){ ... }) ⇒ self
off({ type: handler, type2: handler2, ... }, [selector]) ⇒ self
off(type, [selector]) ⇒ self
off() ⇒ self

Detach event handlers added with on. To detach a specific event handler, the same function must be passed that was used for on(). Otherwise, just calling this method with an event type with detach all handlers of that type. When called without arguments, it detaches all event handlers registered on current elements.

on

on(type, [selector], function(e){ ... }) ⇒ self
on({ type: handler, type2: handler2, ... }, [selector]) ⇒ self

Add event handlers to the elements in collection. Multiple event types can be passed in a space-separated string, or as an object where event types are keys and handlers are values. If a CSS selector is given, the handler function will only be called when an event originates from an element that matches the selector.

Event handlers are executed in the context of the element to which the handler is attached, or the matching element in case a selector is provided. When an event handler returns false, preventDefault() is called for the current event, preventing the default browser action such as following links.

var elem = $('#content')
// observe all clicks inside #content:
elem.on('click', function(e){ ... })
// observe clicks inside navigation links in #content
elem.on('click', 'nav a', function(e){ ... })
// all clicks inside links in the document
$(document).on('click', 'a', function(e){ ... })

one

one(type, function(e){ ... }) ⇒ self
one({ type: handler, type2: handler2, ... }) ⇒ self

Adds an event handler that removes itself the first time it runs, ensuring that the handler only fires once.

trigger

trigger(event, [data])

Trigger the specified event on elements of the collection. Event can either be a string type, or a full event object obtained with $.Event. If a data array is given, it is passed as additional arguments to event handlers.

// add a handler for a custom event
$(document).on('mylib:change', function(e, from, to){
  console.log('change on %o with data %s, %s', e.target, from, to)
})
// trigger the custom event
$(document.body).trigger('mylib:change', ['one', 'two'])

Zepto only supports triggering events on DOM elements.

triggerHandler

triggerHandler(event, [data]) ⇒ self

Like trigger, but triggers only event handlers on current elements and doesn’t bubble.

unbind 🐶🔫

Deprecated, use off instead.

unbind(type, function(e){ ... }) ⇒ self
unbind({ type: handler, type2: handler2, ... }) ⇒ self

Detach event handler added with bind.

undelegate 🐶🔫

Deprecated, use off instead.

undelegate(selector, type, function(e){ ... }) ⇒ self
undelegate(selector, { type: handler, type2: handler2, ... }) ⇒ self

Detach event handler added with delegate.

$.ajax

$.ajax(options) ⇒ XMLHttpRequest

Perform an Ajax request. It can be to a local resource, or cross-domain via HTTP access control support in browsers or JSONP.

Options:

• type (default: “GET”): HTTP request method (“GET”, “POST”, or other)
• url (default: current URL): URL to which the request is made
• data (default: none): data for the request; for GET requests it is appended to query string of the URL. Non-string objects will get serialized with $.param
• processData (default: true): whether to automatically serialize data for non-GET requests to string
• contentType (default: “application/x-www-form-urlencoded”): the Content-Type of the data being posted to the server (this can also be set via headers). Pass false to skip setting the default value.
• dataType (default: none): response type to expect from the server (“json”, “jsonp”, “xml”, “html”, or “text”)
• timeout (default: 0): request timeout in milliseconds, 0 for no timeout
• headers: object of additional HTTP headers for the Ajax request
• async (default: true): set to false to issue a synchronous (blocking) request
• global (default: true): trigger global Ajax events on this request
• context (default: window): context to execute callbacks in
• traditional (default: false): activate traditional (shallow) serialization of data parameters with $.param

If the URL contains =? or dataType is “jsonp”, the request is performed by injecting a <script> tag instead of using XMLHttpRequest (see JSONP). This has the limitation of contentType, dataType, headers, and async not being supported.

Ajax callbacks

You can specify the following callback functions, which are given in order of execution:

1. beforeSend(xhr, settings): before the request is sent. Provides access to the xhr object. Return false from the function to cancel the request

2. success(data, status, xhr): when request succeeds

3. error(xhr, errorType, error): if there is an error (timeout, parse error, or status code not in HTTP 2xx)

4. complete(xhr, status): after the request is complete, regardless of error or success

Ajax events

These events are fired during the lifecycle of an Ajax request performed with the default setting of global: true:

1. ajaxStart (global): fired if no other Ajax requests are currently active

2. ajaxBeforeSend (data: xhr, options): before sending the request; can be cancelled

3. ajaxSend (data: xhr, options): like ajaxBeforeSend, but not cancellable

4. ajaxSuccess (data: xhr, options, data): when the response is success

5. ajaxError (data: xhr, options, error): when there was an error

6. ajaxComplete (data: xhr, options): after request has completed, regardless of error or success

7. ajaxStop (global): fired if this was the last active Ajax request

By default, Ajax events are fired on the document object. However, if the context of a request is a DOM node, the events are fired on that node and will bubble up the DOM. The only exceptions to this are the global events ajaxStart & ajaxStop.

$(document).on('ajaxBeforeSend', function(e, xhr, options){
  // This gets fired for every Ajax request performed on the page.
  // The xhr object and $.ajax() options are available for editing.
  // Return false to cancel this request.
})
$.ajax({
  type: 'GET',
  url: '/projects',
  // data to be added to query string:
  data: { name: '../../../../zepto.js' },
  // type of data we are expecting in return:
  dataType: 'json',
  timeout: 300,
  context: $('body'),
  success: function(data){
    // Supposing this JSON payload was received:
    //   {"project": {"id": 42, "html": "<div>..." }}
    // append the HTML to context object.
    this.append(data.project.html)
  },
  error: function(xhr, type){
    alert('Ajax error!')
  }
})
// post a JSON payload:
$.ajax({
  type: 'POST',
  url: '/projects',
  // post payload:
  data: JSON.stringify({ name: '../../../../zepto.js' }),
  contentType: 'application/json'
})

$.ajaxJSONP 🐶🔫

Deprecated, use $.ajax instead.

$.ajaxJSONP(options) ⇒ mock XMLHttpRequest

Perform a JSONP request to fetch data from another domain.

This method has no advantages over $.ajax and should not be used.

$.ajaxSettings

Object containing the default settings for Ajax requests. Most settings are described in $.ajax. The ones that are useful when set globally are:

• timeout (default: 0): set to a non-zero value to specify a default timeout for Ajax requests in milliseconds
• global (default: true): set to false to prevent firing Ajax events
• xhr (default: XMLHttpRequest factory): set to a function that returns instances of XMLHttpRequest (or a compatible object)
• accepts: MIME types to request from the server for specific dataType values:
  • script: “text/javascript, application/javascript”
  • json: “application/json”
  • xml: “application/xml, text/xml”
  • html: “text/html”
  • text: “text/plain”

$.get

$.get(url, function(data, status, xhr){ ... }) ⇒ XMLHttpRequest
$.get(url, [data], [function(data, status, xhr){ ... }], [dataType]) ⇒ XMLHttpRequest [v1.0]

Perform an Ajax GET request. This is a shortcut for the $.ajax method.

$.get('/whatevs.html', function(response){
  $(document.body).append(response)
})

$.getJSON

$.getJSON(url, function(data, status, xhr){ ... }) ⇒ XMLHttpRequest
$.getJSON(url, [data], function(data, status, xhr){ ... }) ⇒ XMLHttpRequest [v1.0]

Get JSON data via Ajax GET request. This is a shortcut for the $.ajax method.

$.getJSON('/awesome.json', function(data){
  console.log(data)
})
// fetch data from another domain with JSONP
$.getJSON('//example.com/awesome.json?callback=?', function(remoteData){
  console.log(remoteData)
})

$.param

$.param(object, [shallow]) ⇒ string
$.param(array) ⇒ string

Serialize an object to a URL-encoded string representation for use in Ajax request query strings and post data. If shallow is set, nested objects are not serialized and nested array values won’t use square brackets on their keys.

Also accepts an array in serializeArray format, where each item has “name” and “value” properties.

$.param({ foo: { one: 1, two: 2 }})
//=> "foo[one]=1&foo[two]=2)"
$.param({ ids: [1,2,3] })
//=> "ids[]=1&ids[]=2&ids[]=3"
$.param({ ids: [1,2,3] }, true)
//=> "ids=1&ids=2&ids=3"
$.param({ foo: 'bar', nested: { will: 'not be ignored' }})
//=> "foo=bar&nested[will]=not+be+ignored"
$.param({ foo: 'bar', nested: { will: 'be ignored' }}, true)
//=> "foo=bar&nested=[object+Object]"

$.post

$.post(url, [data], function(data, status, xhr){ ... }, [dataType]) ⇒ XMLHttpRequest

Perform an Ajax POST request. This is a shortcut for the $.ajax method.

$.post('/create', { sample: 'payload' }, function(response){
  // process response
})

data can also be a string:

$.post('/create', $('#some_form').serialize(), function(response){
  // ...
})

load

load(url, function(data, status, xhr){ ... }) ⇒ self

Set the html contents of the current collection to the result of a GET Ajax call to the given URL. Optionally, a CSS selector can be specified in the URL, like so, to use only the HTML content matching the selector for updating the collection:

$('#some_element').load('/foo.html #bar')

If no CSS selector is given, the complete response text is used instead.

Note that any JavaScript blocks found are only executed in case no selector is given.

serialize

serialize() ⇒ string

Serialize form values to an URL-encoded string for use in Ajax post requests.

serializeArray

serializeArray() ⇒ array

Serialize form into an array of objects with name and value properties. Disabled form controls, buttons, and unchecked radio buttons/checkboxes are skipped. The result doesn’t include data from file inputs.

$('form').serializeArray()
//=> [{ name: 'size', value: 'micro' },
//    { name: 'name', value: 'Zepto' }]

submit

submit() ⇒ self
submit(function(e){ ... }) ⇒ self

Trigger or attach a handler for the submit event. When no function given, trigger the “submit” event on the current form and have it perform its submit action unless preventDefault() was called for the event.

When a function is given, this simply attaches it as a handler for the “submit” event on current elements.

$.fx

Global settings for animations:

• $.fx.off (default false in browsers that support CSS transitions): set to true to disable all animate() transitions.

• $.fx.speeds: an object with duration settings for animations:

  • _default (400 ms)
  • fast (200 ms)
  • slow (600 ms)

  Change existing values or add new properties to affect animations that use a string for setting duration.

animate

animate(properties, [duration, [easing, [function(){ ... }]]]) ⇒ self
animate(properties, { duration: msec, easing: type, complete: fn }) ⇒ self
animate(animationName, { ... }) ⇒ self

Smoothly transition CSS properties of elements in the current collection.

• properties: object that holds CSS values to animate to; or CSS keyframe animation name
• duration (default 400): duration in milliseconds, or a string:
  • fast (200 ms)
  • slow (600 ms)
  • any custom property of $.fx.speeds
• easing (default linear): specifies the type of animation easing to use, one of:
  • ease
  • linear
  • ease-in / ease-out
  • ease-in-out
  • cubic-bezier(...)
• complete: callback function for when the animation finishes

Zepto also supports the following CSS transform properties:

• translate(X|Y|Z|3d)
• rotate(X|Y|Z|3d)
• scale(X|Y|Z)
• matrix(3d)
• perspective
• skew(X|Y)

If the duration is 0 or $.fx.off is true (default in a browser that doesn’t support CSS transitions), animations will not be executed; instead the target values will take effect instantly. Similarly, when the target CSS properties match the current state of the element, there will be no animation and the complete function won’t be called.

If the first argument is a string instead of object, it is taken as a CSS keyframe animation name.

$("#some_element").animate({
  opacity: 0.25, left: '50px',
  color: '#abcdef',
  rotateZ: '45deg', translate3d: '0,10px,0'
}, 500, 'ease-out')

Zepto exclusively uses CSS transitions for effects and animation. jQuery easings are not supported. jQuery's syntax for relative changes ("=+10px") is not supported. See the spec for a list of animatable properties. Browser support may vary, so be sure to test in all browsers you want to support.

Touch events

The “touch” module adds the following events, which can be used with on and off:

• tap — fires when the element is tapped.
• singleTap and doubleTap — this pair of events can be used to detect both single and double taps on the same element (if you don’t need double tap detection, use tap instead).
• longTap — fires when an element is tapped and the finger is held down for more than 750ms.
• swipe, swipeLeft, swipeRight, swipeUp, swipeDown — fires when an element is swiped (optionally in the given direction)

All these events are also available via shortcut methods on any Zepto collection.

<style>.delete { display: none; }</style>
<ul id=items>
  <li>List item 1 <span class=delete>DELETE</span></li>
  <li>List item 2 <span class=delete>DELETE</span></li>
</ul>
<script>
// show delete buttons on swipe
$('#items li').swipe(function(){
  $('.delete').hide()
  $('.delete', this).show()
})
// delete row on tapping delete button
$('.delete').tap(function(){
  $(this).parent('li').remove()
})
</script>