# reveal.js [![Build Status](https://travis-ci.org/hakimel/reveal.js.png?branch=master)](https://travis-ci.org/hakimel/reveal.js)

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). It's best viewed in a browser with support for CSS 3D transforms but [fallbacks](https://github.com/hakimel/reveal.js/wiki/Browser-Support) are available to make sure your presentation can still be viewed elsewhere.


#### More reading:
- [Installation](#installation): Step-by-step instructions for getting reveal.js running on your computer.
- [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.

## 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 [http://slid.es](http://slid.es).


## Instructions

### Markup

Markup hierarchy needs to be ``
 
 
`` where the ``
`` represents one slide and can be repeated indefinitely. If you place multiple ``
``'s inside of another ``
`` they will be shown as vertical slides. The first of the vertical slides is the "root" of the others (at the top), and it 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,

	// 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,

	// 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,

	// 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', // default/cube/page/concave/zoom/linear/fade/none

	// Transition speed
	transitionSpeed: 'default', // default/fast/slow

	// Transition style for full page slide backgrounds
	backgroundTransition: 'default', // default/none/slide/concave/convex/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"


});
```

Note that the new default vertical centering option will break compatibility with slides that were using transitions with backgrounds (`cube` and `page`). To restore the previous behavior, set `center` to `false`.


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 });
```


### 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, condition: function() { return !!document.body.classList; } },

		// Speaker notes
		{ src: 'plugin/notes/notes.js', async: true, condition: function() { return !!document.body.classList; } },

		// Remote control your reveal.js presentation using a touch device
		{ src: 'plugin/remotes/remotes.js', async: true, condition: function() { return !!document.body.classList; } },

		// 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


### 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: 1.0

});
```


### Auto-sliding

Presentations can be configure 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. Sliding is also 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 by using the ```data-autoslide``` attribute on individual sections:

```html
This will remain on screen for 10 seconds
```


### 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)
  }
});
```


### API

The ``Reveal`` class provides 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();
Reveal.toggleOverview();
Reveal.togglePause();

// Retrieves the previous and current slide elements
Reveal.getPreviousSlide();
Reveal.getCurrentSlide();

Reveal.getIndices(); // { h: 0, v: 0 } }

// State checks
Reveal.isFirstSlide();
Reveal.isLastSlide();
Reveal.isOverview();
Reveal.isPaused();
```

### Ready Event

The 'ready' event is fired when reveal.js has loaded all (synchronous) dependencies and is ready to start navigating.

```javascript
Reveal.addEventListener( 'ready', function( event ) {
	// event.currentSlide, event.indexh, event.indexv
} );
```

### Slide Changed Event

An '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
} );
```


### 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 background colors or images by applying a ```data-background``` attribute to your ```
``` elements. Below are a few examples.

```html

	
All CSS color formats are supported, like rgba() or hsl().


	
This slide will have a full-size background image.


	
This background image will be sized to 100px and repeated.

```

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 two following config properties when initializing reveal.js (the third one is 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)

	// This slide transition gives best results:
	transition: linear

});
```

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!

```

Note that this does not work with the page and cube transitions.


### 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

	
grow
	
shrink
	
roll-in
	
fade-out
	
visible only once
	
blue only once
	
highlight-red
	
highlight-green
	
highlight-blue

```

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](http://softwaremaniacs.org/soft/highlight/en/) 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

	

(def lazy-fib
  (concat
   [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
Reveal.configure({ slideNumber: true });
```


### 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 `