# reveal.js [![Build Status](https://travis-ci.org/hakimel/reveal.js.svg?branch=master)](https://travis-ci.org/hakimel/reveal.js) Slides A framework for easily creating beautiful presentations using HTML. [Check out the live demo](http://lab.hakim.se/reveal-js/). reveal.js comes with a broad range of features including [nested slides](https://github.com/hakimel/reveal.js#markup), [Markdown contents](https://github.com/hakimel/reveal.js#markdown), [PDF export](https://github.com/hakimel/reveal.js#pdf-export), [speaker notes](https://github.com/hakimel/reveal.js#speaker-notes) and a [JavaScript API](https://github.com/hakimel/reveal.js#api). There's also a fully featured visual editor and platform for sharing reveal.js presentations at [slides.com](https://slides.com?ref=github). ## Table of contents - [Online Editor](#online-editor) - [Instructions](#instructions) - [Markup](#markup) - [Markdown](#markdown) - [Element Attributes](#element-attributes) - [Slide Attributes](#slide-attributes) - [Configuration](#configuration) - [Presentation Size](#presentation-size) - [Dependencies](#dependencies) - [Ready Event](#ready-event) - [Auto-sliding](#auto-sliding) - [Keyboard Bindings](#keyboard-bindings) - [Touch Navigation](#touch-navigation) - [Lazy Loading](#lazy-loading) - [API](#api) - [Slide Changed Event](#slide-changed-event) - [Presentation State](#presentation-state) - [Slide States](#slide-states) - [Slide Backgrounds](#slide-backgrounds) - [Parallax Background](#parallax-background) - [Slide Transitions](#slide-transitions) - [Internal links](#internal-links) - [Fragments](#fragments) - [Fragment events](#fragment-events) - [Code syntax highlighting](#code-syntax-highlighting) - [Slide number](#slide-number) - [Overview mode](#overview-mode) - [Fullscreen mode](#fullscreen-mode) - [Embedded media](#embedded-media) - [Stretching elements](#stretching-elements) - [postMessage API](#postmessage-api) - [PDF Export](#pdf-export) - [Theming](#theming) - [Speaker Notes](#speaker-notes) - [Share and Print Speaker Notes](#share-and-print-speaker-notes) - [Server Side Speaker Notes](#server-side-speaker-notes) - [Multiplexing](#multiplexing) - [Master presentation](#master-presentation) - [Client presentation](#client-presentation) - [Socket.io server](#socketio-server) - [MathJax](#mathjax) - [Installation](#installation) - [Basic setup](#basic-setup) - [Full setup](#full-setup) - [Folder Structure](#folder-structure) - [License](#license) #### More reading - [Changelog](https://github.com/hakimel/reveal.js/releases): Up-to-date version history. - [Examples](https://github.com/hakimel/reveal.js/wiki/Example-Presentations): Presentations created with reveal.js, add your own! - [Browser Support](https://github.com/hakimel/reveal.js/wiki/Browser-Support): Explanation of browser support and fallbacks. - [Plugins](https://github.com/hakimel/reveal.js/wiki/Plugins,-Tools-and-Hardware): A list of plugins that can be used to extend reveal.js. ## Online Editor Presentations are written using HTML or Markdown but there's also an online editor for those of you who prefer a graphical interface. Give it a try at [https://slides.com](https://slides.com?ref=github). ## Instructions ### Markup Here's a barebones example of a fully working reveal.js presentation: ```html
Slide 1
Slide 2
``` The presentation markup hierarchy needs to be `.reveal > .slides > section` where the `section` represents one slide and can be repeated indefinitely. If you place multiple `section` elements inside of another `section` they will be shown as vertical slides. The first of the vertical slides is the "root" of the others (at the top), and will be included in the horizontal sequence. For example: ```html
Single Horizontal Slide
Vertical Slide 1
Vertical Slide 2
``` ### Markdown It's possible to write your slides using Markdown. To enable Markdown, add the ```data-markdown``` attribute to your ```
``` elements and wrap the contents in a ```
``` #### External Markdown You can write your content as a separate file and have reveal.js load it at runtime. Note the separator arguments which determine how slides are delimited in the external file. The ```data-charset``` attribute is optional and specifies which charset to use when loading the external file. When used locally, this feature requires that reveal.js [runs from a local web server](#full-setup). ```html
``` #### Element Attributes Special syntax (in html comment) is available for adding attributes to Markdown elements. This is useful for fragments, amongst other things. ```html
``` #### Slide Attributes Special syntax (in html comment) is available for adding attributes to the slide `
` elements generated by your Markdown. ```html
``` ### Configuration At the end of your page you need to initialize reveal by running the following code. Note that all config values are optional and will default as specified below. ```javascript Reveal.initialize({ // Display controls in the bottom right corner controls: true, // Display a presentation progress bar progress: true, // Display the page number of the current slide slideNumber: false, // Push each slide change to the browser history history: false, // Enable keyboard shortcuts for navigation keyboard: true, // Enable the slide overview mode overview: true, // Vertical centering of slides center: true, // Enables touch navigation on devices with touch input touch: true, // Loop the presentation loop: false, // Change the presentation direction to be RTL rtl: false, // Randomizes the order of slides each time the presentation loads shuffle: false, // Turns fragments on and off globally fragments: true, // Flags if the presentation is running in an embedded mode, // i.e. contained within a limited portion of the screen embedded: false, // Flags if we should show a help overlay when the questionmark // key is pressed help: true, // Flags if speaker notes should be visible to all viewers showNotes: false, // Number of milliseconds between automatically proceeding to the // next slide, disabled when set to 0, this value can be overwritten // by using a data-autoslide attribute on your slides autoSlide: 0, // Stop auto-sliding after user input autoSlideStoppable: true, // Use this method for navigation when auto-sliding autoSlideMethod: Reveal.navigateNext, // Enable slide navigation via mouse wheel mouseWheel: false, // Hides the address bar on mobile devices hideAddressBar: true, // Opens links in an iframe preview overlay previewLinks: false, // Transition style transition: 'default', // none/fade/slide/convex/concave/zoom // Transition speed transitionSpeed: 'default', // default/fast/slow // Transition style for full page slide backgrounds backgroundTransition: 'default', // none/fade/slide/convex/concave/zoom // Number of slides away from the current that are visible viewDistance: 3, // Parallax background image parallaxBackgroundImage: '', // e.g. "'https://s3.amazonaws.com/hakim-static/reveal-js/reveal-parallax-1.jpg'" // Parallax background size parallaxBackgroundSize: '', // CSS syntax, e.g. "2100px 900px" // Number of pixels to move the parallax background per slide // - Calculated automatically unless specified // - Set to 0 to disable movement along an axis parallaxBackgroundHorizontal: null, parallaxBackgroundVertical: null }); ``` The configuration can be updated after initialization using the ```configure``` method: ```javascript // Turn autoSlide off Reveal.configure({ autoSlide: 0 }); // Start auto-sliding every 5s Reveal.configure({ autoSlide: 5000 }); ``` ### Presentation Size All presentations have a normal size, that is the resolution at which they are authored. The framework will automatically scale presentations uniformly based on this size to ensure that everything fits on any given display or viewport. See below for a list of configuration options related to sizing, including default values: ```javascript Reveal.initialize({ ... // The "normal" size of the presentation, aspect ratio will be preserved // when the presentation is scaled to fit different resolutions. Can be // specified using percentage units. width: 960, height: 700, // Factor of the display size that should remain empty around the content margin: 0.1, // Bounds for smallest/largest possible scale to apply to content minScale: 0.2, maxScale: 1.5 }); ``` If you wish to disable this behavior and do your own scaling (e.g. using media queries), try these settings: ```javascript Reveal.initialize({ ... width: "100%", height: "100%", margin: 0, minScale: 1, maxScale: 1 }); ``` ### Dependencies Reveal.js doesn't _rely_ on any third party scripts to work but a few optional libraries are included by default. These libraries are loaded as dependencies in the order they appear, for example: ```javascript Reveal.initialize({ dependencies: [ // Cross-browser shim that fully implements classList - https://github.com/eligrey/classList.js/ { src: 'lib/js/classList.js', condition: function() { return !document.body.classList; } }, // Interpret Markdown in
elements { src: 'plugin/markdown/marked.js', condition: function() { return !!document.querySelector( '[data-markdown]' ); } }, { src: 'plugin/markdown/markdown.js', condition: function() { return !!document.querySelector( '[data-markdown]' ); } }, // Syntax highlight for elements { src: 'plugin/highlight/highlight.js', async: true, callback: function() { hljs.initHighlightingOnLoad(); } }, // Zoom in and out with Alt+click { src: 'plugin/zoom-js/zoom.js', async: true }, // Speaker notes { src: 'plugin/notes/notes.js', async: true }, // MathJax { src: 'plugin/math/math.js', async: true } ] }); ``` You can add your own extensions using the same syntax. The following properties are available for each dependency object: - **src**: Path to the script to load - **async**: [optional] Flags if the script should load after reveal.js has started, defaults to false - **callback**: [optional] Function to execute when the script has loaded - **condition**: [optional] Function which must return true for the script to be loaded ### Ready Event A 'ready' event is fired when reveal.js has loaded all non-async dependencies and is ready to start navigating. To check if reveal.js is already 'ready' you can call `Reveal.isReady()`. ```javascript Reveal.addEventListener( 'ready', function( event ) { // event.currentSlide, event.indexh, event.indexv } ); ``` ### Auto-sliding Presentations can be configured to progress through slides automatically, without any user input. To enable this you will need to tell the framework how many milliseconds it should wait between slides: ```javascript // Slide every five seconds Reveal.configure({ autoSlide: 5000 }); ``` When this is turned on a control element will appear that enables users to pause and resume auto-sliding. Alternatively, sliding can be paused or resumed by pressing »a« on the keyboard. Sliding is paused automatically as soon as the user starts navigating. You can disable these controls by specifying ```autoSlideStoppable: false``` in your reveal.js config. You can also override the slide duration for individual slides and fragments by using the ```data-autoslide``` attribute: ```html

After 2 seconds the first fragment will be shown.

After 10 seconds the next fragment will be shown.

Now, the fragment is displayed for 2 seconds before the next slide is shown.

``` To override the method used for navigation when auto-sliding, you can specify the ```autoSlideMethod``` setting. To only navigate along the top layer and ignore vertical slides, set this to ```Reveal.navigateRight```. Whenever the auto-slide mode is resumed or paused the ```autoslideresumed``` and ```autoslidepaused``` events are fired. ### Keyboard Bindings If you're unhappy with any of the default keyboard bindings you can override them using the ```keyboard``` config option: ```javascript Reveal.configure({ keyboard: { 13: 'next', // go to the next slide when the ENTER key is pressed 27: function() {}, // do something custom when ESC is pressed 32: null // don't do anything when SPACE is pressed (i.e. disable a reveal.js default binding) } }); ``` ### Touch Navigation You can swipe to navigate through a presentation on any touch-enabled device. Horizontal swipes change between horizontal slides, vertical swipes change between vertical slides. If you wish to disable this you can set the `touch` config option to false when initializing reveal.js. If there's some part of your content that needs to remain accessible to touch events you'll need to highlight this by adding a `data-prevent-swipe` attribute to the element. One common example where this is useful is elements that need to be scrolled. ### Lazy Loading When working on presentation with a lot of media or iframe content it's important to load lazily. Lazy loading means that reveal.js will only load content for the few slides nearest to the current slide. The number of slides that are preloaded is determined by the `viewDistance` configuration option. To enable lazy loading all you need to do is change your "src" attributes to "data-src" as shown below. This is supported for image, video, audio and iframe elements. Lazy loaded iframes will also unload when the containing slide is no longer visible. ```html
``` ### API The ``Reveal`` object exposes a JavaScript API for controlling navigation and reading state: ```javascript // Navigation Reveal.slide( indexh, indexv, indexf ); Reveal.left(); Reveal.right(); Reveal.up(); Reveal.down(); Reveal.prev(); Reveal.next(); Reveal.prevFragment(); Reveal.nextFragment(); // Randomize the order of slides Reveal.shuffle(); // Toggle presentation states, optionally pass true/false to force on/off Reveal.toggleOverview(); Reveal.togglePause(); Reveal.toggleAutoSlide(); // Change a config value at runtime Reveal.configure({ controls: true }); // Returns the present configuration options Reveal.getConfig(); // Fetch the current scale of the presentation Reveal.getScale(); // Retrieves the previous and current slide elements Reveal.getPreviousSlide(); Reveal.getCurrentSlide(); Reveal.getIndices(); // { h: 0, v: 0 } } Reveal.getProgress(); // 0-1 Reveal.getTotalSlides(); // Returns the speaker notes for the current slide Reveal.getSlideNotes(); // State checks Reveal.isFirstSlide(); Reveal.isLastSlide(); Reveal.isOverview(); Reveal.isPaused(); Reveal.isAutoSliding(); ``` ### Slide Changed Event A 'slidechanged' event is fired each time the slide is changed (regardless of state). The event object holds the index values of the current slide as well as a reference to the previous and current slide HTML nodes. Some libraries, like MathJax (see [#226](https://github.com/hakimel/reveal.js/issues/226#issuecomment-10261609)), get confused by the transforms and display states of slides. Often times, this can be fixed by calling their update or render function from this callback. ```javascript Reveal.addEventListener( 'slidechanged', function( event ) { // event.previousSlide, event.currentSlide, event.indexh, event.indexv } ); ``` ### Presentation State The presentation's current state can be fetched by using the `getState` method. A state object contains all of the information required to put the presentation back as it was when `getState` was first called. Sort of like a snapshot. It's a simple object that can easily be stringified and persisted or sent over the wire. ```javascript Reveal.slide( 1 ); // we're on slide 1 var state = Reveal.getState(); Reveal.slide( 3 ); // we're on slide 3 Reveal.setState( state ); // we're back on slide 1 ``` ### Slide States If you set ``data-state="somestate"`` on a slide ``
``, "somestate" will be applied as a class on the document element when that slide is opened. This allows you to apply broad style changes to the page based on the active slide. Furthermore you can also listen to these changes in state via JavaScript: ```javascript Reveal.addEventListener( 'somestate', function() { // TODO: Sprinkle magic }, false ); ``` ### Slide Backgrounds Slides are contained within a limited portion of the screen by default to allow them to fit any display and scale uniformly. You can apply full page backgrounds outside of the slide area by adding a ```data-background``` attribute to your ```
``` elements. Four different types of backgrounds are supported: color, image, video and iframe. ##### Color Backgrounds All CSS color formats are supported, like rgba() or hsl(). ```html


``` ##### Image Backgrounds By default, background images are resized to cover the full page. Available options: | Attribute | Default | Description | | :--------------------------- | :--------- | :---------- | | data-background-image | | URL of the image to show. GIFs restart when the slide opens. | | data-background-size | cover | See [background-size](https://developer.mozilla.org/docs/Web/CSS/background-size) on MDN. | | data-background-position | center | See [background-position](https://developer.mozilla.org/docs/Web/CSS/background-position) on MDN. | | data-background-repeat | no-repeat | See [background-repeat](https://developer.mozilla.org/docs/Web/CSS/background-repeat) on MDN. | ```html


This background image will be sized to 100px and repeated

``` ##### Video Backgrounds Automatically plays a full size video behind the slide. | Attribute | Default | Description | | :--------------------------- | :------ | :---------- | | data-background-video | | A single video source, or a comma separated list of video sources. | | data-background-video-loop | false | Flags if the video should play repeatedly. | | data-background-video-muted | false | Flags if the audio should be muted. | ```html


``` ##### Iframe Backgrounds Embeds a web page as a background. Note that since the iframe is in the background layer, behind your slides, it is not possible to interact with the embedded page. ```html


``` ##### Background Transitions Backgrounds transition using a fade animation by default. This can be changed to a linear sliding transition by passing ```backgroundTransition: 'slide'``` to the ```Reveal.initialize()``` call. Alternatively you can set ```data-background-transition``` on any section with a background to override that specific transition. ### Parallax Background If you want to use a parallax scrolling background, set the first two config properties below when initializing reveal.js (the other two are optional). ```javascript Reveal.initialize({ // Parallax background image parallaxBackgroundImage: '', // e.g. "https://s3.amazonaws.com/hakim-static/reveal-js/reveal-parallax-1.jpg" // Parallax background size parallaxBackgroundSize: '', // CSS syntax, e.g. "2100px 900px" - currently only pixels are supported (don't use % or auto) // Number of pixels to move the parallax background per slide // - Calculated automatically unless specified // - Set to 0 to disable movement along an axis parallaxBackgroundHorizontal: 200, parallaxBackgroundVertical: 50 }); ``` Make sure that the background size is much bigger than screen size to allow for some scrolling. [View example](http://lab.hakim.se/reveal-js/?parallaxBackgroundImage=https%3A%2F%2Fs3.amazonaws.com%2Fhakim-static%2Freveal-js%2Freveal-parallax-1.jpg¶llaxBackgroundSize=2100px%20900px). ### Slide Transitions The global presentation transition is set using the ```transition``` config value. You can override the global transition for a specific slide by using the ```data-transition``` attribute: ```html

This slide will override the presentation transition and zoom!

Choose from three transition speeds: default, fast or slow!

``` You can also use different in and out transitions for the same slide: ```html
The train goes on …
and on …
and stops.
(Passengers entering and leaving)
And it starts again.
``` ### Internal links It's easy to link between slides. The first example below targets the index of another slide whereas the second targets a slide with an ID attribute (```
```): ```html Link Link ``` You can also add relative navigation links, similar to the built in reveal.js controls, by appending one of the following classes on any element. Note that each element is automatically given an ```enabled``` class when it's a valid navigation route based on the current slide. ```html ``` ### Fragments Fragments are used to highlight individual elements on a slide. Every element with the class ```fragment``` will be stepped through before moving on to the next slide. Here's an example: http://lab.hakim.se/reveal-js/#/fragments The default fragment style is to start out invisible and fade in. This style can be changed by appending a different class to the fragment: ```html




fade-up (also down, left and right!)

visible only once

blue only once




``` Multiple fragments can be applied to the same element sequentially by wrapping it, this will fade in the text on the first step and fade it back out on the second. ```html
I'll fade in, then out
``` The display order of fragments can be controlled using the ```data-fragment-index``` attribute. ```html

Appears last

Appears first

Appears second

``` ### Fragment events When a slide fragment is either shown or hidden reveal.js will dispatch an event. Some libraries, like MathJax (see #505), get confused by the initially hidden fragment elements. Often times this can be fixed by calling their update or render function from this callback. ```javascript Reveal.addEventListener( 'fragmentshown', function( event ) { // event.fragment = the fragment DOM element } ); Reveal.addEventListener( 'fragmenthidden', function( event ) { // event.fragment = the fragment DOM element } ); ``` ### Code syntax highlighting By default, Reveal is configured with [highlight.js](https://highlightjs.org/) for code syntax highlighting. Below is an example with clojure code that will be syntax highlighted. When the `data-trim` attribute is present, surrounding whitespace is automatically removed. HTML will be escaped by default. To avoid this, for example if you are using `` to call out a line of code, add the `data-noescape` attribute to the `` element. ```html

(def lazy-fib
   [0 1]
   ((fn rfib [a b]
        (lazy-cons (+ a b) (rfib b (+ a b)))) 0 1)))
``` ### Slide number If you would like to display the page number of the current slide you can do so using the ```slideNumber``` configuration value. ```javascript // Shows the slide number using default formatting Reveal.configure({ slideNumber: true }); // Slide number formatting can be configured using these variables: // "h.v": horizontal . vertical slide number (default) // "h/v": horizontal / vertical slide number // "c": flattened slide number // "c/t": flattened slide number / total slides Reveal.configure({ slideNumber: 'c/t' }); ``` ### Overview mode Press "Esc" or "o" keys to toggle the overview mode on and off. While you're in this mode, you can still navigate between slides, as if you were at 1,000 feet above your presentation. The overview mode comes with a few API hooks: ```javascript Reveal.addEventListener( 'overviewshown', function( event ) { /* ... */ } ); Reveal.addEventListener( 'overviewhidden', function( event ) { /* ... */ } ); // Toggle the overview mode programmatically Reveal.toggleOverview(); ``` ### Fullscreen mode Just press »F« on your keyboard to show your presentation in fullscreen mode. Press the »ESC« key to exit fullscreen mode. ### Embedded media Embedded HTML5 `