var modalCurrentOn = null;
function modalChange ( id ) {
	if ( modalCurrentOn != null ) {
		modalOff( modalCurrentOn );
	}
	modalCurrentOn = getElementById( id );
	modalOn( modalCurrentOn );
}
function modalOn ( elem ) {
	if ( !elem ) {
		elem = modalCurrentOn;
	}
	elem.style.display = 'block';
	getElementById('modal-area').style.display = 'block';
}
function modalOff ( elem ) {
	if ( !elem ) {
		elem = modalCurrentOn;
	}
	elem.style.display = 'none';
	getElementById('modal-area').style.display = 'none';
}