<html>
<head>
<script type="text/javascript" src="jquery1.8.3.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$(".field").change(function(){
$('.field1').val($(".field").val());
});
});
</script>
</head>
<body>
Enter your name: <input class="field1" type="text" />
<p>Car:
<select class="field" name="cars">
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="fiat">Fiat</option>
<option value="audi">Audi</option>
</select>
</p>
</body>
</html>