function set_class(what,what_class)
	{
		document.getElementById(what).className = ''+what_class+'';
	}
	
	function show_product(product){
	
		for(i = 1; i <= 4; i++)
		{
			
			if(document.getElementById("product-"+i))
			{
				document.getElementById("product-"+i).style.visibility = 'hidden';
			}
		
			document.getElementById(product).style.visibility = 'visible';
		}
	
	}