// Add this to impvars.php:

  // Calculator, default currencies in ISO code
  $from_currency = 'USD';
  $target_currency = 'NOK';

// Below are the new contents of calculator.php, simply replace all of it
<?
require_once('impvars.php');
$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);
?>
<script type="application/javascript">
function UpdateCurrency()
{
    var amount = document.getElementById('amount');
    var from = document.getElementById('from');
    var target = document.getElementById('target');
    var targetvalue = target.options[target.selectedIndex].value;
    var fromvalue = from.options[from.selectedIndex].value;
    <?
    $queryjs = "SELECT currency_USD FROM currencies";
    $datajs = mysqli_query($dbc, $queryjs);
    $rowjs = mysqli_fetch_array($datajs);
    $USD = $rowjs['currency_USD'];
    ?>
    if (fromvalue == <?=$USD?>)
    {
        converted = amount.value * targetvalue;
    }
    else
    {
        var convertedhalf = amount.value / fromvalue;
        converted = convertedhalf * targetvalue;
    }
    document.getElementById('convertedmoney').innerHTML= amount.value + ' ' + from.options[from.selectedIndex].innerHTML + ' = ' + converted + ' ' + target.options[target.selectedIndex].innerHTML;
}
</script>
<?
$query = "SELECT * FROM currencies";
$data2 = mysqli_query($dbc, $query);
$row2 = mysqli_fetch_array($data2);
$query = "SELECT * FROM currencies_names";
$data3 = mysqli_query($dbc, $query);
$row3 = mysqli_fetch_array($data3);
$currentcolumn = "currency_AFN";
?>
<strong>Amount</strong>
<input type="text" id="amount" onChange="UpdateCurrency()" />
<br />
<strong>From</strong>
<select id="from" onChange="UpdateCurrency()">
<?
$query = "SELECT * FROM currencies_abbr";
$data = mysqli_query($dbc, $query);
while ($row = mysqli_fetch_array($data)) {
$currentcolumn = "currency_" . $row['abbrevation'];
if(!empty($row3[$currentcolumn]) && !empty($row2[$currentcolumn]))
    {
        if ($row['abbrevation'] == $from_currency) {
            ?>
    <option value="<? echo $row2[$currentcolumn]; ?>" selected><? echo $row3[$currentcolumn];  ?></option>
            <?
        }
        else {
    ?>
    <option value="<? echo $row2[$currentcolumn]; ?>"><? echo $row3[$currentcolumn];  ?></option>
    <?
        }
    }
}
?>
</select>
<strong>To</strong>
<select id="target" onChange="UpdateCurrency()">
<?
$query = "SELECT * FROM currencies_abbr";
$data = mysqli_query($dbc, $query);
while ($row = mysqli_fetch_array($data)) {
$currentcolumn = "currency_" . $row['abbrevation'];
if(!empty($row3[$currentcolumn]) && !empty($row2[$currentcolumn]))
    {
        if ($row['abbrevation'] == $target_currency) {
            ?>
            <option value="<? echo $row2[$currentcolumn]; ?>" selected><? echo $row3[$currentcolumn];  ?></option>
            <?
        }
        else {
    ?>
    <option value="<? echo $row2[$currentcolumn]; ?>"><? echo $row3[$currentcolumn];  ?></option>
    <?
        }
    }
}
mysqli_close($dbc);
?>
</select>

<br />
<span id="convertedmoney"></span>