Ajax Without Refreshing Problem

[portseven]

Tag,

Ich möchte, dass beim betätigen des Button, die Seite nicht neu ladet.

kann mir jemand mal verraten was ich falsch mache?!

	while($row = $stmt->fetch()) {
	$sql4 ="
	SELECT 
	comments.u_id,
	comments.p_id,
	u_post.u_id,
	u_post.p_id
	
	FROM comments
	
	LEFT JOIN u_post
	ON comments.p_id = u_post.p_id
	
	WHERE comments.p_id = ?";
	
	$new = $pdo->prepare($sql4);
	$new->BindValue(1, $row['p_id']);
	if(!$new->execute()) {
	print_r($new->errorInfo());
	}
	
	$countss = $new->rowCount();
	
	$row4 = $new->fetch();
	
	echo '<div id="form-content">'; 
	echo '<form method="POST" id="reg-form" autocomplete="off">';
	echo '<br>Post-Id: '. $row['p_id'] . '<br>' .  $row['post'] . '<br>';
	echo 'Kommentare: ' . $countss . ' <br> ';
		if($_POST['post-id'] === $row['p_id']) {
			while($row2 = $result->fetch()) {
				echo 'Kommentar: ' . $row2['comment'] .'<br>';
		}
	}
		echo '<p><input type="submit" name="show" id="show"></p>';
		echo '<p><input type="hidden" name="post-id" value="' . $row['p_id'] . '"></p>';
		echo '_____________________';
	echo '</form>';
	echo '</div>';
}

?>
		<script src="jQuery/jquery-3.3.1.min.js">
        $("#show").click( function()
        {
                $.ajax({
                url: "test.php",
                type: 'POST',
                success: function(result) { 
                //finished
         }
         });
         });
        </script>