adds a datepicker calendar to your specified Event Espresso text field question

datepicker.php

<?php
//* Please do NOT include the opening php tag, except of course if you're starting with a blank file

// datepicker jQuery for Event Espresso 3
// 

add_action('wp_enqueue_scripts', 'my_custom_espresso_scripts');

function my_custom_espresso_scripts() {
	global $load_espresso_scripts;

	if ( ! $load_espresso_scripts )
		return;
	// load jQuery UI scripts from WP Core
	wp_enqueue_script('jquery-ui-core');
	wp_enqueue_script('jquery-ui-datepicker');
	// load up a theme (you can set your own theme below if you did not activate the themeroller option in ee3)
	// in this example, it's loading up the Cupertino theme
	wp_enqueue_style('jquery-ui-css',
                'http://ajax.googleapis.com/ajax/libs/jqueryui/1.10.3/themes/cupertino/jquery-ui.css',
                false,
                1.0,
                false);
}


add_action('wp_footer', 'my_custom_datepicker_input');

function my_custom_datepicker_input() {
	global $load_espresso_scripts;

	if ( ! $load_espresso_scripts )
		return;
	?>
	<script>jQuery(document).ready(function($){
		// set the input class as the selector below, in this example, it's Question ID 13
		$( ".TEXT_13" ).datepicker();
	});
	</script>
	<?php
}