Kod do przepisania
<?php
$kursy=['USD'=>4.5,'EUR'=>4.7,'GBP'=>5.2];
if(isset($_POST['pln'])){
$pln = (float)$_POST['pln'];
$waluta=$_POST['waluta'];
if(isset($kursy[$waluta])){
$wynik=$pln/$kursy[$waluta];
echo "<p>$pln PLN = ".round($wynik,2)." $waluta</p>";
}
}
?>
<form method="post">
Kwota PLN: <input type="number" step="0.01" name="pln" required><br>
Waluta:
<select name="waluta">
<option value="USD">USD</option>
<option value="EUR">EUR</option>
<option value="GBP">GBP</option>
</select><br>
<input type="submit" value="Przelicz">
</form>