//aanmaken custom velden bij Series
function gmm_custom_box_Series_html($post){
	$value_Seasons = get_post_meta($post->ID, '_seasons', true);
	$value_Start = get_post_meta($post->ID, '_start', true);
	$value_End = get_post_meta($post->ID, '_end', true);
	print("<div>");
	print("Serie year start:");
	print("<input type='number' id='start' name='start' value='". $value_Start . "'");
	print("</div>");
	print("<br/>");

	print("<div>");
	print("Serie year End:");
	print("<input type='number' id='end' name='end' value='". $value_End . "'");
	print("</div>");
	print("<br/>");

	print("<div>");
	print("Season amount:  ");
	print("<input type='number' id='seasons' name='seasons' value='". $value_Seasons . "'");
	print("</div>");
	print("<br/>");
}