PHP-在按下按钮后显示数组中的一个值

Question

当您单击按钮“提交”时，我希望一个值同时显示在网站上。如果再次单击它，则应该显示数组中的另一个值，依此类推。

我看不到我在做什么错。现在，当我单击按钮时，什么也没有显示。

我创建一个按钮。

<form action="index.php" method="post">
 <input type="submit" name="randomRoad" value="Submit"> 
</form>

我的PHP代码

<?php
 if($_POST['randomRoad'] === 'Submit'){ 

  $roadDirections = array(
      "straight",
      "straight",
      "straight",
      "straight",
      "left",
      "left",
      "left",
      "left",
      "right",
      "right",
      "right",
      "right",
    );

    $correct = true;
    $userGuess = $roadDirections;

  while ($correct == false) { 
    $random = mt_rand(0, count($userGuess) -1);
    $guessed = $userGuess[$random];
    echo "<p>" .  $guessed;

    if ($guessed == $roadDirections[$correct]) {
      $correct = true;
      array_splice($userGuess, $random, 1);
      echo " YES!";
    }
    else {
      echo " NO!";
    }
  }
}

它还应根据值是否正确来回显“是”或“否”。