Conditional Input

<!DOCTYPE html>
<html>
  <head>
    <title>Conditional Input</title>
  </head>
  <body>
    <div id='container'>
      <div id='input_box'>
        <form method="POST">
          <table border='1'>
            <tr>
              <td>Ketertarikan</td>
              <td>
                <input type='radio' name='field' value='sm' checked='checked'/> Sangat Menarik<br/>
                <input type='radio' name='field' value='me'/> Menarik<br/>
                <input type='radio' name='field' value='km'/> Kurang Menarik
              </td>
            </tr>
            <tr>
              <td>Berikan nilai untuk Ketertarikan</td>
              <td><input name="nilai" /> Nilai rentang 10-100</td>
            </tr>
            <tr>
              <td colspan="2">
                <input type="submit" value="kirim" />
              </td>
          </table>
        </form>
      </div>
      <div id='result_box'>
<?php
if(isset($_POST['nilai']))
{
  echo "INSERT INTO table(sm,me,km) VALUES("
       .($_POST['field']=='sm'?$_POST['nilai']:"0").","
       .($_POST['field']=='me'?$_POST['nilai']:"0").","
       .($_POST['field']=='km'?$_POST['nilai']:"0").")";
}
?>
      </div>
    </div>
  </body>
</html>