 cubic-bezier(0.42, 0, 0.58, 1.0)">
<style>
  div {
    height: 100px;
    transition: width 2s;
    width: 100px;
  }
  #test1 {
    background-color: blue;
    transition-timing-function: ease-in-out;
  }
  #test2 {
    background-color: yellow;
    transition-timing-function: cubic-bezier(0.42, 0, 0.58, 1.0);
  }
</style>
<body>
  <p>Click the 'Start' button. Test passes if the width growth of blue square is <strong>equivalent</strong> to the yellow square.</p>
  <div id="test1"></div>
  <div id="test2">