Split header, banner - how to implement?

Question

css

How to test a page, for example, with different headers or banners?
Is there such a mechanism as with the animation of the 'wow' plugin, for example? When filling out the form, the result of loading the session (with animation or not) is recorded in the database.

if (!isset($_SESSION["split"]) || !$_SESSION["split"]) {
    $values = array("wow", "no_wow");
    $rand = mt_rand(0, count($values) - 1);
      /*записываем в сессию случ.знач.кот.выпало от 0 до 1*/
    $_SESSION["split"] = $values[$rand];
     }