function toggleSession (id) {
	var session_id = id.replace('session', '');
	var inputs = $$('#sessions input');
	inputs.each(function (input) {
		var parent = input.getProperty('parent');
		if (parent == 0) {
			if (input.getProperty('full')) {
				input.setProperty('disabled', 'disabled');
			}
		} else {
			if (!$('session' + parent).getProperty('checked') || input.getProperty('full')) {
				input.setProperty('disabled', 'disabled');
			} else {
				input.removeProperty('disabled');
			}
		}
	});
}

function validateSessions () {
	var inputs = $$('#sessions input[required=required]');
	if (inputs.length > 0) {
		for (var i = 0; i < inputs.length; i++) {
			if (inputs[i].getProperty('checked')) {
				return true;
			}
		}
		alert('Please specify which session you would like to attend');
		return false;
	} else {
		return true;
	}
}

function openEmsPopup (event, popup) {
	window.open(
		'/events/popup/?event=' + event + '&popup=' + popup, 
		'emsPopup', 
		'width=400,height=300,resizable=yes,scrollbars=yes'
	);
}

window.addEvent('domready', function () {
	toggleSession('session0');
});