function chgcurrency(id,price,currency,select,USD,EUR,GBP,CHF)
{
var newcurrency = select.value;

switch (newcurrency)
{
case "BGN":
  newcurrency=1;
  break
case "USD":
  newcurrency=USD;
  break
case "EUR":
  newcurrency=EUR;
  break
case "GBP":
  newcurrency=GBP;
  break
case "CHF":
  newcurrency=CHF;
  break
}

switch (currency)
{
case "BGN":
  currency=1;
  break
case "USD":
  currency=USD;
  break
case "EUR":
  currency=EUR;
  break
case "GBP":
  currency=GBP;
  break
case "CHF":
  currency=CHF;
  break
}
bgnprice=Math.round(price*currency);
newprice=Math.round(bgnprice/newcurrency);

document.getElementById(id).innerHTML=newprice;
}