function summa() {

		var order_list = document.getElementById('order_list');
		var order_list_elems = order_list.getElementsByTagName('span');
		
		var price = 0;
		var price_summa = 0;

		for(var i=0; i<order_list_elems.length; i++) {
			
			if (document.getElementById(i).checked)
			{
				price = order_list_elems[i].innerHTML;
				price = price.replace(' ','');
				price_summa = price_summa + parseInt(price);
			}
		}

		document.getElementById('order_summa').innerHTML = price_summa;
	}