Encrypt Function Display First ID Field From Form

When I run the following code the script will not display the second id field from the form:
function enCrypt( code ){
var form = document.getElementById( 'myForm' );
document.write(form.cipher.value);
document.write(form.msgcode.value);
} // end function enCrypt
</script>
<form id = "myForm" action = "">
<p>Enter cipher : <input id = "cipher" type = "text" /></p>
<p>Enter message : <input id = "msgcode" type = "text" /></p>
<p>Result : <input id = "result" type = "text" /></p>
<input type = "button" value = "Encrypt"
onclick = "enCrypt()" />