Ecco un esempio:
Codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Prova</title>
<script type="text/javascript">
<!--
function select_change ()
{
var f = document.form1;
f.text1.value = f.elenco.options[f.elenco.selectedIndex].text;
}
//-->
</script>
</head>
<body>
<form name="form1">
<select name="elenco" onchange="select_change()">
<option value="1">elemento 1</option>
<option value="2">elemento 2</option>
<option value="3">elemento 3</option>
</select>
<br>
<input type="text" name="text1" size="20">
</form>
</body>
</html>