Untitled

<!DOCTYPE HTML>
<html lang="pl">
<head>
    <meta charset="utf-8" />
    <title>Test</title>
    <meta name="description" content="test" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />

    <link rel="stylesheet" href="style.css" type="text/css" />
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
    <script src="jquery.mask.js"></script>

    <script>
        $(document).ready(function(){
            $('#postcode').mask('00/00/0000');
    });
    </script>

</head>

<body>

    <div id="containerlogin">
        <form>

            <input type="text" placeholder="Postcode" name="postcode" id="postcode">

            <input type="submit"value="">

        </form>
    </div>

</body>
</html>