function keisan(){
	var tax = 5; // 消費税率

	// 商品1
	var kosuu1 = document.sell.item1.value;
	var tanka1 = 880;
	var price1 = kosuu1 * tanka1;
	document.getElementById('price1').innerHTML = price1;

	// 商品2
	var kosuu2 = document.sell.item2.value;
	var tanka2 = 880;
	var price2 = kosuu2 * tanka2;
	document.getElementById('price2').innerHTML = price2;

	// 商品3
	var kosuu3 = document.sell.item3.value;
	var tanka3 = 880;
	var price3 = kosuu3 * tanka3;
	document.getElementById('price3').innerHTML = price3;
	
	// 商品4
	var kosuu4 = document.sell.item4.value;
	var tanka4 = 880;
	var price4 = kosuu4 * tanka4;
	document.getElementById('price4').innerHTML = price4;

	// 商品5
	var kosuu5 = document.sell.item5.value;
	var tanka5 = 140;
	var price5 = kosuu5 * tanka5;
	document.getElementById('price5').innerHTML = price5;

	// 商品6
	var kosuu6 = document.sell.item6.value;
	var tanka6 = 140;
	var price6 = kosuu6 * tanka6;
	document.getElementById('price6').innerHTML = price6;

	// 商品7
	var kosuu7 = document.sell.item7.value;
	var tanka7 = 140;
	var price7 = kosuu7 * tanka7;
	document.getElementById('price7').innerHTML = price7;

	// 商品8
	var kosuu8 = document.sell.item8.value;
	var tanka8 = 140;
	var price8 = kosuu8 * tanka8;
	document.getElementById('price8').innerHTML = price8;

	// 商品9
	var kosuu9 = document.sell.item9.value;
	var tanka9 = 140;
	var price9 = kosuu9 * tanka9;
	document.getElementById('price9').innerHTML = price9;

	// 商品10
	var kosuu10 = document.sell.item10.value;
	var tanka10 = 580;
	var price10 = kosuu10 * tanka10;
	document.getElementById('price10').innerHTML = price10;

	// 商品11
	var kosuu11 = document.sell.item11.value;
	var tanka11 = 580;
	var price11 = kosuu11 * tanka11;
	document.getElementById('price11').innerHTML = price11;

	// 商品12
	var kosuu12 = document.sell.item12.value;
	var tanka12 = 840;
	var price12 = kosuu12 * tanka12;
	document.getElementById('price12').innerHTML = price12;
	
	// 商品13
	var kosuu13 = document.sell.item13.value;
	var tanka13 = 840;
	var price13 = kosuu13 * tanka13;
	document.getElementById('price13').innerHTML = price13;
	
	// 商品14
	var kosuu14 = document.sell.item14.value;
	var tanka14 = 840;
	var price14 = kosuu14 * tanka14;
	document.getElementById('price14').innerHTML = price14;

	// 合計を計算
	var field_total1 = price1 + price2 + price3 + price4 + price5 + price6 + price7 + price8 + price9 + price10 + price11 + price12 + price13 + price14;
	document.getElementById('field_total1').innerHTML = field_total1;
	document.sell.field_total1.value = field_total1;

	// 送料
	var souryou_price = document.sell.souryou.options[document.sell.souryou.selectedIndex].value;
	var s_tanka = 1;
	var s_price = souryou_price * s_tanka;

	// 税込合計を表示
	var field_total2 = field_total1 + s_price;
	document.getElementById('field_total2').innerHTML = Math.floor(field_total2);
	document.sell.field_total2.value = Math.floor(field_total2);
}