JavaScript Tutorial

.fadeTo()

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>fadeTo demo</title>
  <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
    <p>
        Click this paragraph to see it fade.
    </p>
    <p>
        Compare to this one that won't fade.
    </p>
    <script>
        $( "p:first" ).click(function() {
          $( this ).fadeTo( "slow", 0.33 );
        });
    </script>
</body>
</html>