prova così
Codice PHP:
<form name="form" method="post" action="">
<table width="600" border="0">
<tr>
<td>
<input type="checkbox" name="piatto[1]" value="pizza"> pizza
<input type="hidden" name="value[1]" value="10.00" />
</td>
<td>
<input type="checkbox" name="piatto[2]" value="pasta"> pasta </td>
<input type="hidden" name="value[2]" value="10.00" />
<td>
<input type="checkbox" name="piatto[3]" value="pollo"> pollo </td>
<input type="hidden" name="value[3]" value="pollo" />
<input type="submit" name="calcola" value="calcola">
</form>
<?php
$piatti=array();
foreach($_POST['piatto'] as $key=>$value){
if($value != "") $piatti[$value]=$_POST['value'][$key];
}
foreach($piatti as $piatto=>$costo){
echo "hai scelto: $piatto che costa $costo
";
}
?>