function showExpand(obj) 
{
	var number = obj.getAttribute('number')
	if (obj.id == number + "_on") 
	{
		obj.style.display = 'none';
		document.getElementById(number + "_off").style.display = 'block';
	}
	else 
	{
		obj.style.display = 'none';
		document.getElementById(number + "_on").style.display = 'block';
	}
}