function showYen() {
var pay =0;
  pay = parseInt((document.calcu.baht.value*100.00)/36.13); 
  document.calcu.yen.value = pay;
}
function showYen2() {
var pay =0;
  pay = parseInt((document.calcu2.baht.value*100.00)/36.13); 
  document.calcu2.yen.value = pay;
}
<!--3gyomet_to_8gyome_no_suji_ha_ranchubasu_no_toppage_bangkokbank_no_en_buy_no_suji_wo_ireru-->