Google API: Google Place Autocomplete for Postal (Zip) Code using JavaScript

<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?libraries=places&key=AIzaSyBE1J5Pe_GZXBR_x9TXOv6TU5vtCSmEPW4"></script>
<script type="text/javascript">
    window.onload = function () {
        var postal = document.getElementById('postalCode');
        var options = { types: ['(regions)'] }
        var autocomplete = new google.maps.places.Autocomplete(postal, options);
    }
</script>
<input id="postalCode" type="text" size="50" autocomplete="off">