Dynamics.js is a JavaScript library to create physics-based animations

To see some demos, check out dynamicsjs.com.



npm install dynamics.js
  • bower:
bower install dynamics.js

Include dynamic.js into your page:

<script src="dynamics.js"></script>

You can animate CSS properties of any DOM element.

var el = document.getElementById("logo")
dynamics.animate(el, {
  translateX: 350,
  scale: 2,
  opacity: 0.5
}, {
  type: dynamics.spring,
  frequency: 200,
  friction: 200,
  duration: 1500

You also can animate SVG properties.

var path = document.querySelector("path")
dynamics.animate(path, {
  d: "M0,0 L0,100 L100,50 L0,0 Z",
  fill: "#FF0000",
  rotateZ: 45,
  // rotateCX and rotateCY are the center of the rotation
  rotateCX: 100,
  rotateCY: 100
}, {
  friction: 800

And any JavaScript object.

var o = {
  number: 10,
  color: "#FFFFFF",
  string: "10deg",
  array: [ 1, 10 ]
dynamics.animate(o, {
  number: 20,
  color: "#000000",
  string: "90deg",
  array: [-9, 99 ]


dynamics.animate(el, properties, options)

Animates an element to the properties with the animation options.

  • el is a DOM element, a JavaScript object or an Array of elements
  • properties is an object of the properties/values you want to animate
  • options is an object representing the animation
    • type is the animation type: dynamics.springdynamic.easeInOut … (default: dynamics.easeInOut)
    • frequencyfrictionbounciness,… are specific to the animation type you are using
    • duration is in milliseconds (default: 1000)
    • delay is in milliseconds (default: 0 )
    • complete (optional) is the completion callback
    • change (optional) is called at every change. Two arguments are passed to the function. function(el, progress) 
      • el is the element it’s animating
      • progress is the progress of the animation between 0 and 1


Stops the animation applied on the element

dynamics.css(el, properties)

This is applying the CSS properties to your element with the correct browser prefixes.

  • el is a DOM element
  • properties is an object of the CSS properties

dynamics.setTimeout(fn, delay)

Dynamics.js has its own setTimeout . The reason is that requestAnimationFrame and setTimeout have different behaviors. In most browsers, requestAnimationFrame will not run in a background tab while setTimeout will. This can cause a lot of problems while using setTimeout along your animations. I suggest you use Dynamics’s setTimeout and clearTimeout to handle these scenarios.

  • fn is the callback
  • delay is in milliseconds

Returns a unique id


Clears a timeout that was defined earlier

  • id is the timeout id


Toggle a debug mode to slow down every animations and timeouts. This is useful for development mode to tweak your animation. This can be activated using Shift+Control+D in the browser.

Dynamics and properties


  • frequency default is 300
  • friction default is 200
  • anticipationSize (optional)
  • anticipationStrength (optional)


  • frequency default is 300
  • friction default is 200

dynamics.forceWithGravity and dynamics.gravity

  • bounciness default is 400
  • elasticity default is 200

dynamics.easeInOut, dynamics.easeIn and dynamics.easeOut

  • friction default is 500


No properties


  • points array of points and control points

The easiest way to output this kind of array is to use the curve creator. Here is an example:




 npm run build


npm run build:watch

Run tests: 

npm test

Browser Support

Working on

  • Safari 7+
  • Firefox 35+
  • Chrome 34+
  • IE10+


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