Featherlight – ultra slim jQuery lightbox
Featherlight is a very lightweight jQuery lightbox plugin. For more information and demos, visit the official website.

Simple yet flexible
Image, Ajax, iFrame and custom content support
Gallery Extension
Minimal CSS
Name-spaced CSS and JavaScript
Customizable via javascript or attributes

» Download Current Release 1.7.14
Here you’ll find a list of all the changes and you can also download old releases or the master including all the latest bling.
All styling is done using CSS so you’ll want to include the Featherlight CSS in your head.

Be aware that Featherlight uses very unspecific CSS selectors to help you overwrite every aspect. This means in turn, that if you’re not following a modularized approach to write CSS (which you should! It’s terrific!) and have many global and specific definitions (read ID’s and such – which you shouldn’t), these definitions can break the Featherlight styling.
Featherlight requires jQuery version 1.7.0 or higher (regular version, not the slim one). It’s recommended to include the javascript at the bottom of the page before the closing tag.

By default, featherlight acts on all elements using the ‘data-featherlight’ attribute. An element with this attribute triggers the lightbox. The value of the attribute acts as selector for an element that’s opened as lightbox.
Open element in lightbox

This div will be opened in a lightbox

Featherlight is smart. ‘data-featherlight’ can also contain a link to an image, an ajax-url or even DOM code:
Open image in lightbox
Open ajax content in lightbox
Open image in lightbox
Open ajax content in lightbox
Open ajax content in lightbox
Open ajax content in lightbox

By default, Featherlight initializes all elements matching $.featherlight.autoBind on document ready. If you want to prevent this, set $.featherlight.autoBind to false before the DOM is ready.
Bind Featherlight
You can bind the Featherlight events on any element using the following code:
$(‘.myElement’).featherlight($content, configuration);

It will then look for the targetAttr (by default “data-featherlight”) on this element and use its value to find the content that will be opened as lightbox when you click on the element.
$content – jQuery Object or String: You can manually pass a jQuery object or a string (see content filters) to be opened in the lightbox. Optional
configuration – Object: Object to configure certain aspects of the plugin. See Configuration. Optional
Manual calling of Featherlight
In cases where you don’t want an Element to act as Trigger you can call Featherlight manually. You can use this for example in an ajax callback to display the response data.
$.featherlight($content, configuration);

$content – jQuery Object or String: You can manually pass a jQuery object or a string (see content filters) to be opened in the lightbox. Optional
configuration – Object: Object to configure certain aspects of the plugin. See Configuration. Optional
Featherlight comes with a bunch of configuration-options which make it very flexible.
These options can be passed when calling featherlight.
Alternatively, they can specified as attribute on the elements triggering the lightbox;
for example, has the same effect as
passing {closeOnEsc: false}.
You can also modify the $.featherlight.defaults directly which holds all the defaults:
/* you can access and overwrite all defaults using $.featherlight.defaults */defaults: {    namespace:      ‘featherlight’,        /* Name of the events and css class prefix */    targetAttr:     ‘data-featherlight’,   /* Attribute of the triggered element that contains the selector to the lightbox content */    variant:        null,                  /* Class that will be added to change look of the lightbox */    resetCss:       false,                 /* Reset all css */    background:     null,                  /* Custom DOM for the background, wrapper and the closebutton */    openTrigger:    ‘click’,               /* Event that triggers the lightbox */    closeTrigger:   ‘click’,               /* Event that triggers the closing of the lightbox */    filter:         null,                  /* Selector to filter events. Think $(…).on(‘click’, filter, eventHandler) */    root:           ‘body’,                /* A selector specifying where to append featherlights */    openSpeed:      250,                   /* Duration of opening animation */    closeSpeed:     250,                   /* Duration of closing animation */    closeOnClick:   ‘background’,          /* Close lightbox on click (‘background’, ‘anywhere’, or false) */    closeOnEsc:     true,                  /* Close lightbox when pressing esc */    closeIcon:      ‘✕’,            /* Close icon */    loading:        ”,                    /* Content to show while initial content is loading */    persist:        false,                 /* If set, the content will persist and will be shown again when opened again. ‘shared’ is a special value when binding multiple elements for them to share the same content */    otherClose:     null,                  /* Selector for alternate close buttons (e.g. “a.close”) */    beforeOpen:     $.noop,                /* Called before open. can return false to prevent opening of lightbox. Gets event as parameter, this contains all data */    beforeContent:  $.noop,                /* Called when content is about to be presented. `this` is the featherlight instance. Gets event as parameter */    beforeClose:    $.noop,                /* Called before close. can return false to prevent closing of lightbox. `this` is the featherlight instance. Gets event as parameter  */    afterOpen:      $.noop,                /* Called after open. `this` is the featherlight instance. Gets event as parameter  */    afterContent:   $.noop,                /* Called after content is ready and has been set. Gets event as parameter, this contains all data */    afterClose:     $.noop,                /* Called after close. `this` is the featherlight instance. Gets event as parameter  */    onKeyUp:        $.noop,                /* Called on key up for the frontmost featherlight */    onResize:       $.noop,                /* Called after new content and when a window is resized */    type:           null,                  /* Specify content type. If unset, it will check for the targetAttrs value. */    contentFilters: [‘jquery’, ‘image’, ‘html’, ‘ajax’, ‘text’] /* List of content filters to use to determine the content */    jquery/image/html/ajax/text: undefined /* Specify content type and data */}
namespace – String: ‘featherlight’

All functions bound to elements are namespaced. This is also used to prefix all CSS classes for the background, the content-wrapper and the close button.
targetAttr – String: ‘data-featherlight’

Attribute on the triggering element pointing to the target element or content that will be opened in the lightbox.
variant – String: null

Pass your own CSS class to adjust the styling of the lightbox according to your need.
resetCss – Boolean: false

Set this to true to remove all default css and start from designing scratch.
openTrigger & closeTrigger – String: ‘click’

Events that are used to open or close the lightbox. The close event is bound to the close button and to the lightbox background (if enabled).
Has no effect if $.featherlight is called directly.
filter – String: null

A selector to filter events, when calling featherlight on a jQuery set, in a similar fashion to $(…).on(‘click’, filter, eventHandler).
Attributes both the selector and the filtered element are taken into account.
In the following example, the first link will make an ajax request while the second will display the text “second”.


root – String: ‘body’

This selector specified where the featherlight should be appended.
openSpeed & closeSpeed – Integer or String: 250

Defines the speed for the opening and close animations. Values allowed are jQuery animation durations. Avoid the usage of 0 since this would cause a reversal of time and the end of the world! (Okay, kidding, just the closing callback would not be fired and unused ghost-DOM would linger around, but still.)
closeOnClick – ‘background’, ‘anywhere’ or false

If set, the close event is also bound to the either the background only or anywhere
closeOnEsc – Boolean: true

If true, the lightbox is closed when pressing the ESC key
closeIcon – String: ‘✕’;

Oh the naming…
loading – String: ”;

Shown initially while content loads. The lightbox also has a class ‘.featherlight-loading’ while content is loading. This makes it easy to specify a “Loading…” message or a spinner.
persist – Boolean or ‘shared’: false;

If set, the content will persist and will be shown again when opened again.
In case where multiple buttons need to persist the same content, use the special value ‘shared’.
The content filter jquery (used for links like .some-class or #some-id) will clone the given content if and only if it is not persisted. Otherwise it will be moved into the lightbox.
otherClose – String: null

While the close icon generated by featherlight will have class ‘featherlight-close’, you may specify alternate selector for other buttons having the same effect in your dialog, for example “a:contains(‘Cancel’)”.
background – DOM String: null

You can provide the wrapping DOM. This is a bit tricky and just for the advanced users. It’s recommended to study the plugin code. But you need to provide an element with a “{namespace}-inner” class: the content of the lightbox will replace this element. It is recommended that instead of providing this option you modify the lightbox on beforeOpen or afterOpen.
beforeOpen, beforeClose – Function: null

Called before the open or close method is executed. This function can return false to prevent open or
close method from execution. this is an object and contains the triggering DOM element (if existing) and the related Featherlight objects.
// example
beforeOpen: function(event){
console.log(this); // this contains all related elements
return false; // prevent lightbox from opening

beforeContent, afterContent – Function: null

Called before and after the loading of the content. For ajax calls or images, there can be a significant delay, for inline content the two calls will occur one right after the other. It receives the event object. this is an object and contains the triggering DOM element (if existing) and the related Featherlight objects.
afterOpen, afterClose – Function: null

Called after the open or close method is executed – it is not called, if the before- or open function returns false! It receives the event object. this is an object and contains the triggering DOM element (if existing) and the related Featherlight objects.
// example
afterOpen: function(event){
console.log(this); // this contains all related elements
alert(this.$content.hasClass(‘true’)); // alert class of content

onKeyUp, onResize – Function: null

The function receives the event object. this is an object and contains the triggering DOM element (if existing) and the related Featherlight objects.
type – String: null

The type object allows you to manually set what type the lightbox is. Set the value to ‘image’, ‘ajax’ or any of the content filters. Otherwise, the value from targetAttr will used be to determine the type of the lightbox. Example:
$(‘.image-lightbox’).featherlight({type: ‘image’});

$.featherlight is actually a constructor of new featherlight objects. Modify $.featherlight.prototype to change the default properties, or use the configuration object passed to the constructor to override the properties of that specific new instance.
It’s possible to use or change these methods, but the API isn’t guaranteed to remain constant; enquire if you have particular needs.
var current = $.featherlight.current();
// do something else; // reopen it

Check the source code for more details.
$.featherlight has the following globals:
autoBind: ‘[data-featherlight]’ /* Will automatically bind elements matching this selector. Clear or set before onReady */
current: function() /* returns the currently opened featherlight, or undefined */
close: function() /* closes the currently opened featherlight (if any) */

Content Filters
There are many ways to specify content to featherlight. Featherlight uses a set of heuristics to determine the type, for example data ending with .gif will be assumed to be an image. The following are equivalent:
See in a lightbox

See in a lightbox

See in a lightbox

In case the heuristic wouldn’t work, you can specify which contentFilter to use:
See in a lightbox

See in a lightbox

See in a lightbox

You can add your own heuristics, for example:
$.featherlight.contentFilters.feed = {
regex: /^feed:/,
process: function(url) { /* deal with url */ return $(‘Loading…’); }

This way the following would be possible:
See the feed in a lightbox

The content filter ‘text’ needs to be specified explicitly, it has no heuristic attached to it:

Use link-hashtags to open lightbox


targetAttr: ‘href’

Open images with Featherlight
Use a link and point the data-featherlight attribute to the desired attribute which contains the link…
Open Image

…or directly provide the link as the data-featherlight attribute:
Open Image

Open lightbox with ajax content
Use Featherlight with ajax using ‘ajax’ keyword or providing a url. It even supports selecting elements inside the response document.
Open Ajax Content

or you can provide the link directly as the featherlight-attribute:
Open Ajax Content

Open lightbox with iframe
Featherlight generates an iframe with the ‘iframe’ keyword and a given URL.
The default size of the iframe is very small (300 x 150).
Open in an iframe

You can use the following iframe attributes:
allow, allowfullscreen, frameborder, height, longdesc, marginheight, marginwidth, mozallowfullscreen, name, referrerpolicy, sandbox, scrolling, src, srcdoc, style, webkitallowfullscreen, width
For example, to set the height and width, you would use
data-featherlight-iframe-height=”640″ data-featherlight-iframe-width=”480″

or to set some css style:

You can also set the iframe attributes iframeWidth, iframeMinWidth etc. using JavaScript:
$.featherlight({iframe: ‘editor.html’, iframeMaxWidth: ‘80%’, iframeWidth: 500,
iframeHeight: 300});

Open YouTube video with Featherlight
Featherlight generates an iframe that contains the embedded video.
Display a clickable thumbnail image that opens a video with a fixed size of 640 x 480 and automatically start playback:

A text link that opens a video in a lightbox that is stretched to 85% height and width of the viewport:
My video
A link that opens a video in a lightbox that fills 100% of the window:
Note: the “close” icon is not visible so this example is not user-friendly.
My video
IE8 background transparency
If you want the background in IE8 to be translucent, use data:image before the rgba background:
background: url(data:image/png;base64,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);
background: rgba(0, 0, 0, 0.8);

Featherlight Gallery
You will need to use an extension ( Since Featherlight was created to be as small and simple as possible, it has selected functionality, and allows you to add additional functionality by using extensions. is a small extension that turns your set of links into a gallery.
Gallery installation
Simply include the extension CSS and JavaScript Files after the regular featherlight files like this:

Add the JavaScript at the bottom of the body:
Check out the example here: Gallery with Featherlight
Gallery configuration
The gallery also has a range of configuration options and the following defaults:
    $(‘’).featherlightGallery({        previousIcon: ‘◀’,     /* Code that is used as previous icon */        nextIcon: ‘▶’,         /* Code that is used as next icon */        galleryFadeIn: 100,          /* fadeIn speed when slide is loaded */        galleryFadeOut: 300          /* fadeOut speed before slide is loaded */    });
It also overrides its autoBind global option:
    autoBind: ‘[data-featherlight-gallery]’ /* Will automatically bind elements matching this selector. Clear or set before onReady */
Example in pure HTML:
          This is a gallery                

Example in JavaScript (assuming there are a tags of class gallery in the page):
    $(‘’).featherlightGallery({        previousIcon: ‘«’,        nextIcon: ‘»’,        galleryFadeIn: 300,         openSpeed: 300    });
The gallery responds to custom events previous and next to navigate to the previous and next images.
Instead of navigation buttons it will use swipe events on touch devices, assuming that one of the supported swipe libraries is also installed.
It sets the classes ‘featherlight-first-slide’ and ‘featherlight-last-slide’ if the current slide is the first and/or last one.
Gallery installation
Simply include the extension CSS and JavaScript Files after the regular featherlight files like this:

Gallery on Mobile Devices
To support mobile/tablet and all touch devices, you will need to include one of the supported swipe libraries. For example, to use swipe_detect library, include it in the header:
For questions, please use Stack Overflow and be sure to use the featherlight.js tag. Please provide an example, starting for example from this jsfiddle
Reporting bugs and issues
If you believe you’ve found a bug, please open an issue on Github and provide an example starting from this jsfiddle.
Pull requests
Pull requests are welcome (good tips can be found on Stack Overflow)
To run the tests, you can open test/featherlight.html or test/featherlight_gallery.html in your browser.
Alternatively, run them from the console with grunt test; you will need to run npm install the first time.

GitHub Repo