function updatesum() {

var n = (document.coin_coin.koers.value -0) * (document.coin_coin.coin.value -0);
document.coin_coin.euro.value = n.toFixed(2);
totaalbetalen2();
}

function totaalbetalen() {
var n = (document.coin_coin.koers.value -0) * (document.coin_coin.coin.value -0);
document.coin_coin.pay.value = n.toFixed(2);
totaalbetalen2();
}


function updatesum2() {
var n = (document.coin_coin.euro.value -0) / (document.coin_coin.koers.value -0);
document.coin_coin.coin.value = n.toFixed(8);
totaalbetalen2();
}

function totaalbetalen2() {

	var costs = $('#pg_value option:selected').attr('data-percentage');
	var piece = $('#pg_value option:selected').attr('data-piece')*1.21;
	var n = (document.coin_coin.euro.value -0) / 100 * costs * 1.21;
	var tr = parseFloat(n, 10) + parseFloat(piece, 10);
	document.getElementById("transaction_costs").innerHTML = "€";
	document.getElementById("transaction_costs").innerHTML += tr.toFixed(2);
	document.getElementById("coins_to_receive").innerHTML = document.coin_coin.coin.value;

	var total_costs = (document.coin_coin.euro.value -0) + (tr -0);

	document.getElementById("total_price").innerHTML = "€";
	document.getElementById("total_price").innerHTML += total_costs.toFixed(2);

}