codice:
<html>
<head>
<title>Programma</title>

<script>
function sposta()
{
if(document.modulo.casella.value.length >0){
document.modulo.casella2.value =document.modulo.casella.value;
}else{
document.modulo.casella.value =document.modulo.casella2.value;
}
}
</script>
</head>
<body>
<form name="modulo">
<fieldset>
<legend>Sposta testo</legend>
<inputtype="text"name="casella">
<inputtype="text"name="casella2">
<inputtype="button"value="Sposta il testo"onclick="sposta()">
</fieldset>
</form>
</body>
</html>