var daysdisc;
  var daysdisc;
  var costdisc;
function init(){
  daysdisc = document.forms['reservation'].elements['daysdisc'];
  qtydisc = document.forms['reservation'].elements['QuantityStandardScooter'];
  costdisc = document.forms['reservation'].elements['costdisc'];
  }
function doTheMath(x){
 if(x == 1){
  if(daysdisc.value <= 3) costdisc.value = 75 * daysdisc.value * qtydisc.value;
 }
}

function checkstate(){
 if (daysdisc.value != ''){
  if(qtydisc.value != ''){
   //doTheMath(1);
  }
 }
}

window.onload = init();