var last_selected='';
function contentBlock(obj_id){
	if(last_selected == obj_id){
		if(document.getElementById(obj_id).style.display=='none')
			document.getElementById(obj_id).style.display='block';
		else
			document.getElementById(obj_id).style.display='none';
	}else{
		document.getElementById(obj_id).style.display='block';
		if(last_selected!='')
			document.getElementById(last_selected).style.display='none';
	}
	last_selected = obj_id;
	return false;
}