function chgContinue(sel){

if( sel.value =="継続購入を申し込む"){

document.getElementById('price').value="5800";

}else{

document.getElementById('price').value="6300";

}


chgQty();

}

function chgQty(){

document.getElementById('goukei').value = document.getElementById('price').value * document.getElementById('qty').value;

}

function chgkeizoku(){
document.getElementById('keizoku_goukei').value = 5800 * document.getElementById('keizoku').value;
}