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2.3.4 • Public • Published

AOS - Animate on scroll library

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Small library to animate elements on your page as you scroll.

You may say it's like WOWJS, yeah - you're right, effect is similar to WOWJS, but I had a different idea how to make such a plugin, so here it is. CSS3 driven scroll animation library.

AOS allows you to animate elements as you scroll down, and up. If you scroll back to top, elements will animate to it's previous state and are ready to animate again if you scroll down.

👉 To get a better understanding how this actually works, I encourage you to check my post on CSS-tricks.

🚀 Demo

🌟 Codepen Examples

❗ Attention

From version 2.0.0 attributes aos are no longer supported, always use data-aos.

⚙ Setup

Install AOS

  • Using bower

      bower install aos --save
  • Using npm

      npm install aos --save
  • Direct download -> click here

Link styles

  <link rel="stylesheet" href="bower_components/aos/dist/aos.css" />

Add scripts

  <script src="bower_components/aos/dist/aos.js"></script> 

AOS from version 1.2.0 is available as UMD module, so you can use it as AMD, Global, Node or ES6 module.

Init AOS


🤔 How to use it?

Basic usage

All you have to do is to add data-aos attribute to html element, like so:

  <div data-aos="animation_name">

Script will trigger "animation_name" animation on this element, if you scroll to it.

Down below is a list of all available animations for now :)

🔥 Advanced settings

These settings can be set both on certain elements, or as default while initializing script (in options object without data- part).

Attribute Description Example value Default value
data-aos-offset Change offset to trigger animations sooner or later (px) 200 120
data-aos-duration *Duration of animation (ms) 600 400
data-aos-easing Choose timing function to ease elements in different ways ease-in-sine ease
data-aos-delay Delay animation (ms) 300 0
data-aos-anchor Anchor element, whose offset will be counted to trigger animation instead of actual elements offset #selector null
data-aos-anchor-placement Anchor placement - which one position of element on the screen should trigger animation top-center top-bottom
data-aos-once Choose wheter animation should fire once, or every time you scroll up/down to element true false

*Duration accept values from 50 to 3000, with step 50ms, it's because duration of animation is handled by css, and to not make css longer than it is already I created implementations only in this range. I think this should be good for almost all cases.

If not, you may write simple CSS on your page that will add another duration option value available, for example:

  body[data-aos-duration='4000'] [data-aos][data-aos][data-aos][data-aos-duration='4000']{
    transition-duration: 4000ms;

This code will add 4000ms duration available for you to set on AOS elements, or to set as global duration while initializing AOS script.

Notice that double [data-aos][data-aos] - it's not a mistake, it is a trick, to make individual settings more important than global, without need to write ugly "!important" there :)

data-aos-anchor-placement - You can set different placement option on each element, the principle is pretty simple, each anchor-placement option contains two words i.e. top-center. This means that animation will be triggered when top of element will reach center of the window. bottom-top means that animation will be triggered when bottom of an element reach top of the window, and so on. Down below you can find list of all anchor-placement options.


  <div data-aos="fade-zoom-in" data-aos-offset="200" data-aos-easing="ease-in-sine" data-aos-duration="600">
  <div data-aos="flip-left" data-aos-delay="100" data-aos-anchor=".example-selector">
  <div data-aos="fade-up" data-aos-anchor-placement="top-center">


AOS object is exposed as a global variable, for now there are three methods available:

  • init - initialize AOS
  • refresh - recalculate all offsets and positions of elements (called on window resize)
  • refreshHard - reinit array with AOS elements and trigger refresh (called on DOM changes that are related to aos elements)

Example execution:


By default AOS is watching for DOM changes and if there are any new elements loaded asynchronously or when something is removed from DOM it calls refreshHard automatically. In browsers that don't support MutationObserver like IE you might need to call AOS.refreshHard() by yourself.

refresh method is called on window resize and so on, as it doesn't require to build new store with AOS elements and should be as light as possible.

Global settings

If you don't want to change setting for each element separately, you can change it globally.

To do this, pass options object to init() function, like so:

      offset: 200,
      duration: 600,
      easing: 'ease-in-sine',
      delay: 100,

Additional configuration

These settings can be set only in options object while initializing AOS.

Setting Description Example value Default value
disable Condition when AOS should be disabled mobile false
startEvent Name of event, on which AOS should be initialized exampleEvent DOMContentLoaded
Disabling AOS

If you want to disable AOS on certain device or under any statement you can set disable option. Like so:

      disable: 'mobile'

There are several options that you can use to fit AOS perfectly into your project, you can pass one of three device types: mobile (phones and tablets), phone or tablet. This will disable AOS on those certains devices. But if you want make your own condition, simple type your statement instead of device type name:

  disable: window.innerWidth < 1024

There is also posibility to pass a function, which should at the end return true or false:

  disable: function () {
    var maxWidth = 1024;
    return window.innerWidth < maxWidth;
Start event

If you don't want to initialize AOS on DOMContentLoaded event, you can pass your own event name and trigger it whenever you want. AOS is listening for this event on document element.

      startEvent: 'someCoolEvent'

Important note: If you set startEvent: 'load' it will add event listener on window instead of document.

👻 Animations

There are serveral predefined animations you can use already:

  • Fade animations:

    • fade
    • fade-up
    • fade-down
    • fade-left
    • fade-right
    • fade-up-right
    • fade-up-left
    • fade-down-right
    • fade-down-left
  • Flip animations:

    • flip-up
    • flip-down
    • flip-left
    • flip-right
  • Slide animations:

    • slide-up
    • slide-down
    • slide-left
    • slide-right
  • Zoom animations:

    • zoom-in
    • zoom-in-up
    • zoom-in-down
    • zoom-in-left
    • zoom-in-right
    • zoom-out
    • zoom-out-up
    • zoom-out-down
    • zoom-out-left
    • zoom-out-right

Anchor placement:

  • top-bottom
  • top-center
  • top-top
  • center-bottom
  • center-center
  • center-top
  • bottom-bottom
  • bottom-center
  • bottom-top

Easing functions:

You can choose one of these timing function to animate elements nicely:

  • linear
  • ease
  • ease-in
  • ease-out
  • ease-in-out
  • ease-in-back
  • ease-out-back
  • ease-in-out-back
  • ease-in-sine
  • ease-out-sine
  • ease-in-out-sine
  • ease-in-quad
  • ease-out-quad
  • ease-in-out-quad
  • ease-in-cubic
  • ease-out-cubic
  • ease-in-out-cubic
  • ease-in-quart
  • ease-out-quart
  • ease-in-out-quart

✌️ Contributing

📝 Changelog


If you have any questions, ideas or whatsoever, please check AOS contribution guide and don't hesitate to create new issues.




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  • michalsnik