function enrol_get_dates() {

	new Ajax.Updater('course_date', 'ajax_course_dates.php', {
		method: 'get',
		parameters: {
			page: 'enrol',
			course_type: $('course_type').value,
			course_loc: $('course_loc').value
		}
	});

}

Event.observe(window, 'load', function() {

	if($('enrol')) {
		$('course_type').observe('change', enrol_get_dates);
		$('course_loc').observe('change', enrol_get_dates);
	}

	if($('show_dates')) {
		$('show_dates').observe('click', function(event) {
			new Ajax.Updater('course_dates_list', 'ajax_course_dates.php', {
				method: 'get',
				parameters: { 
					course_type: $('course_type').value,
					course_loc: $('course_loc').value
				}
			});
		});
	}

});