Gravity Forms - Datepicker extension for Date Range Fields

dateform.js

jQuery(function ($) {

	var datepickerInArgs = {
		minDate: 1,
		defaultDate: 0,
		dateFormat: 'dd/mm/yy',
		changeMonth: true,
		changeYear: true,
		onClose: function( dateText, inst ) {
			var d = $.datepicker.parseDate( inst.settings.dateFormat, dateText );
			d.setDate( d.getDate() + 1 );
			$( '.date-out input' )
				.val( $.datepicker.formatDate( inst.settings.dateFormat, d ) )
				.datepicker( 'option', {
				minDate: $.datepicker.formatDate( inst.settings.dateFormat, d )
			});
		}
	},
	datepickerOutArgs = {
		minDate: 'd',
		defaultDate: 'd',
		dateFormat: 'dd/mm/yy',
		changeMonth: true,
		changeYear: false,
	};

	/**
	 * Reset datepicker fields with new arguments.
	 */
	function changeDatepickerArgs() {
		$( '.date-in input, .date-out input' ).datepicker( 'destroy' );

		$( '.date-in input' ).datepicker( datepickerInArgs );
		$( '.date-out input' ).datepicker( datepickerOutArgs );
	}

	$( document ).on( 'gform_post_render', changeDatepickerArgs );
});

//Thanks to Gary Jones https://github.com/garyjones for the code reveiew (and subsequent rewrite)

functions.php

<?php

//Conditionally Enqueue the Script - not on Admin and only on Contact Page template

// Add CSS class to Gravity Input field for Date Picker
// Requires setting the Description in the forms with default content
add_action('gform_field_css_class', 'twp_custom_input_class', 10, 3);
	function twp_custom_input_class($classes, $field, $form){
    if($field['description'] == 'Arrival'){
        $classes .= " date-in";
    }
    if($field['description'] == 'Departure'){
        $classes .= " date-out";
    }
    return $classes;
}

style.css

/* Restore the Calendar Icon to the Date fields
Positioning will vary according to your styles*/

.page-template-page-contact-php .gfield.date-in .ginput_container,
.page-template-page-contact-php .gfield.date-out .ginput_container{
	background: url(http://cyc.org.au/wp-content/plugins/gravityforms/images/calendar.png) no-repeat 41% 50%;
}