title: Why do developers write CSS animation rule without prefix?
body: <p>I wanted to ask that as every browser has its prefix for animation then why developers write a property without any prefix. Look at this example taken from <a href="http://www.w3schools.com/css/css3_2dtransforms.asp" rel="nofollow noreferrer">w3schools.com</a>:</p>
  
  <pre><code>div {
      -ms-transform: scale(0.5,0.5); /* IE 9 */
      -webkit-transform: scale(0.5,0.5); /* Safari */
      transform: scale(0.5,0.5);
  }
  </code></pre>
  
  <p>Why does the second last line exist?</p>