var openItem = '';

function toggle_display( divid ) {
	if( openItem == '' ) {
		document.getElementById( divid ).style.display = 'block';
		openItem = divid;
	} else if( openItem == divid ) {
		document.getElementById( divid ).style.display = 'none';
		openItem = '';
	} else {
		document.getElementById( openItem ).style.display = 'none';
		document.getElementById( divid ).style.display	= 'block';
		openItem = divid;
	}
}