function show_details ( span ) {
	document.getElementById( "detail" + span ).style.display = 'block';
	document.getElementById( "preview" + span ).style.display = 'none';
}

function close_details ( span ) {
	document.getElementById( "detail" + span ).style.display = 'none';
	document.getElementById( "preview" + span ).style.display = 'block';
}