function chk(){
	// 非表示
	if (document.getElementById("credit_form").same.checked){ document.getElementById('shipping').style.display = "none"; }
	// 表示
	else{ document.getElementById('shipping').style.display = "block"; }
}
function calc(num){
	document.getElementById('credit_form').elements["ext"+num].value = (((document.getElementById('credit_form').elements["price"+num].value.split(",").join("") * 100) * document.getElementById('credit_form').elements["qty"+num].value) / 100);
	// 桁区切りを入れる場合
	//var extension = document.getElementById('credit_form').elements["qty"+num].value * document.getElementById('credit_form').elements["price"+num].value.split(",").join("");
	//extension = String(extension);
	//while(extension != (extension = extension.replace(/^(-?\d+)(\d{3})/, "$1,$2")));
	//document.getElementById('credit_form').elements["ext"+num].value = extension;
}