function show(id)
{
	document.getElementById(id).getElementsByTagName('img')[0].style.visibility='visible'
	switchVisibility.addElement(id + '_preview', 'show');
}
function hide(id)
{
	document.getElementById(id).getElementsByTagName('img')[0].style.visibility='hidden'
	switchVisibility.addElement(id + '_preview', 'hide');
}
var switchVisibility = new SwitchVisibility('switchVisibility');