<input type="text" name="email" placeholder="Email" value="<?php if(isset($_GET['e'])) echo $_GET['e']; elseif(isset($_POST['email'])) echo $_POST['email']; elseif(isset($_COOKIE['e'])) echo $_COOKIE['e']; ?>">
<?= isset($_GET['e']) ? $_GET['e'] : (isset($_POST['email']) ? $_POST['email'] : (isset($_COOKIE['e']) ? $_COOKIE['e'] : null)) ?>
<?= isset($getE = $_GET['e']) ? $getE : (isset($postEmail = $_POST['email']) ? $postEmail : (isset($cookieE = $_COOKIE['e']) ? $cookieE : null)) ?>
test.php?e="><script>alert(1)</script>