Código PHP:
Ver original<html>
<head>
<meta http-equiv="Content-Language" content="es-ve">
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<title>Pagina nueva 1</title>
</head>
<body>
<form method="POST" action="register.php">
<p><select size="1" name="vanio" onChange="document.getElementById('id_text').value = this.value;">
<option selected value="1">2006</option>
<option value="2">2007</option>
<option value="3">2008</option>
<option value="4">2009</option>
<option value="5">2010</option>
</select> <input type="text" name="quantity1" size="20"></p>
<input type="text" id="id_text">
</form>
</body>
</html>
Espero haber ayudado