php echo div class hide Регистрация div switch _GET act default echo f

<?php
echo '<div class = "hide">Регистрация</div>';

switch ($_GET['act']){
	default:
		echo '<form action = "?act=ok" method = "POST">';
		echo '<div class = "block">';
		echo 'Ник: <br />
		<input type = "text" name = "nick"> <br />
		Имя: <br />
		<input type = "text" name = "name"> <br />
		Пароль: <br />
		<input type = "text" name = "password"> <br />
		<input type = "submit" name = "go">';
		echo '</div></form>';
	break;

	case 'ok':
		if (isset($_POST['go'])){
			$error = array();

			$nick = $_POST["nick"];
			$name = $_POST["name"];
			$pass = $_POST["password"];
			
			if(!isset($nick)) $errors[] = "Ошибка";
			if(!isset($pass)) $errors[] = "Ошибка";
			if(strlen($pass)<6 || strlen($pass)>32) $errors[] = "Ошибка";
			if(preg_match("/\=|\+|\{|\}|\(|\)|\^|\%|\\$|#|@|!|&|\~|'|\"|:|;|`|,|\.|\?|<|>/",$nick)) $errors[] = "Ошибка";

			if(empty($errors)){
				//db::getInstance()-> query("INSERT INTO `users` SET `id` = 'NULL', `nick` = '".$nick."', `password` = '".md5($pass)."', `name` = '".$name."'"); 
				echo "INSERT INTO `users` SET `id` = 'NULL', `nick` = '".$nick."', `password` = '".md5($pass)."', `name` = '".$name."'";
				echo '<div class = "block">
				Регистрация прошла успешно.<br />
				Ник: '.$nick.'<br />
				Пароль: '.$pass.' <br />
				<a href = "/">Войти</a>
				</div>';
			}else{
				echo "<div class=\"error\">\n".implode("<br>\n", $errors)."</div>\n<br><a href=\"".$_SERVER["HTTP_REFERER"]."\"><img src=\"img/back.gif\">Назад</a>\n";
			}

		}
	break;
}