codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//IT">
<html>
<head>

<script type="text/javascript">
<!--
function testo() {
if (document.getElementById("vari").checked==true) {
document.getElementById("docUscita").value = "vari";
}
else {
document.getElementById("docUscita").value = "";
}
}
-->
</script>
</head>

<body leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">


<div align="center">

<form>
<input name="docUscita" id="docUscita" maxlength="20" size="20">
<input name="vari" id="vari" value="true" type="checkbox" onclick="testo();"> Docs vari
</form>

</div>
</body>
</html>