Delivery Form with jQuery

gistfile1.html

<form id="checkDelivery">
	<label for="postcode">Enter your postcode</label>
	<input type="text" required name="postcode"/>
	<button class="button">Submit</button>
</form>
<div id="delivery_options"></div>

<script>
$('#checkDelivery').submit(function() {
	var data = $(this).serializeArray(),
	    postcodes = [2015,2019,2011];
	jQuery.each(data, function(i, field){
		if ( $.inArray(parseInt(field.value), postcodes) != -1 ) {
			$('#delivery_options').html('<p>Yes, we deliver to your area!</p>');
		}
		else {
			$('#delivery_options').html('<p>Unfortunately, we do not deliver to your area.</p>');
		}
	});
	return false;
});
</script>