Something

<form action="index.php" method="get">Første nummer: <input type="text" name="first" maxlength="6"><br/>Andre nummer: <input type="text" name="second" maxlength="6"><br/><br/>Type:<select name="type">	<option value="pluss">Pluss</option>	<option value="minus">Minus</option>	<option value="dele">Dele</option>	<option value="gange">Gange</option></select><br/><br/><input type="submit" value="Hax it!"></form><?php$type = $_GET['type'];if (ctype_digit($_GET['first'])) {	$first = $_GET['first'];}else {	echo "<span style=\"color:red;font-weight:bold\">Only numberz!!</span>";}if (ctype_digit($_GET['second'])) {	$second = $_GET['second'];}else {	echo "<span style=\"color:red;font-weight:bold\">Only numberz!!</span>";}switch ($type) {case "pluss":	$resultat = $first + $second;	echo "Resultat: $first + $second = $resultat";	break;case "minus":	$resultat = $first - $second;	echo "Resultat: $first - $second = $resultat";	break;case "dele":	$resultat = $first / $second;	echo "Resultat: $first / $second = $resultat";	break;case "gange":	$resultat = $first * $second;	echo "Resultat: $first x $second = $resultat";	break;}?>