function price_calc() {

	//距離と料金の初期化
	var distance = eval(document.calcform.distance.value);
	var price = 0;

	if (distance == 0) { price = 0;}
	else if (distance <= 25) { price = 4700;}
	else if (distance >= 26 && distance <= 30) { price = 5250; }
	else if (distance >= 31 && distance <= 50) { price = 5500 + ((distance - 30) * 200); }
	else if (distance >= 51 && distance <= 100) { price = 9500 + ((distance - 50) * 150); }
	else if (distance >= 101) { price = 17000 + ((distance - 100) * 100);}

	//合計テキストフィールドに代入
	document.calcform.price.value = price;

}