Allowing Users to Use the Carriage Return to submit a form

I have a form that I need to allow users to scan in data into a field. The barcode that they are scanning has a carriage return at the end. I need to allow that carriage return to submit the form rather than having them hit enter. I tried to use some JavaScript to do this but I am having no luck. Here is my code:

<?php
include 'include/connect.include';
$page="New Orders";

include 'include/header.include';

?>
<SCRIPT LANGUAGE="JavaScript">
<!--

function checkEnter(e)
{ //e is event object passed from function invocation
      var characterCode //literal character code will be stored in this variable

      if(e && e.which)
      { //if which property of event object is supported (NN4)
            e = e
            characterCode = e.which //character code is contained in NN4's which property
      }
      else
      {
            e = event
            characterCode = e.keyCode //character code is contained in IE's keyCode property
      }
      //alert(e);
      if(characterCode == 13)
      { //if generated character code is equal to ascii 13 (if enter key)
            document.forms[0].submit() //submit the form
            return false
      }
      else
      {
            return true
      }

}

-->
</script>

<?php

      if(isset($_GET['error']))
      {
            $error = $_GET['error'];
            print "<font color='red'><b>$error</font></b><br>";
            
      }
if(!isset($_REQUEST['new']) && !isset($_GET['pk']))
{
      ?>
      <!-- <form action='new_orders.php' method='post'> -->
      <table>
      <tr>
      <td>Supervisor:</td><td><input type='text' name='supervisor'></td>
      <td>Picker:</td><td><input type='text' name='picker'></td>
      <td><input type='submit' name='new' class='bn' value='Submit'></td>
      </tr>
      </table>
      </form>
      <?php
}
else
{      
      
      if(isset($_REQUEST['supervisor']))
      {$supervisor = $_REQUEST['supervisor'];}
      if(isset($_GET['sv']))
      {$supervisor=$_REQUEST['sv'];}

      if(isset($_REQUEST['picker']))
      {$picker = $_REQUEST['picker'];}
      if(isset($_GET['pk']))
      {$picker = $_GET['pk'];}

      $query = "SELECT * FROM orders WHERE picker = '$picker' AND qa = '0' AND inv_issue='0'
      AND packed='0' AND xship='0' AND ship_confirm='0' AND xship_issue='0'";
      $result = mysql_query($query) or die(mysql_error());
      $line = mysql_fetch_array($result);
      if(mysql_numrows($result) > 0)
      {
            $supervisor = $line['supervisor'];
            $picker = $line['picker'];
            print "<font color='red'><b>Attention:This picker already has an active pick list.</font></b><br>";
      }
      if(isset($_GET['error']))
      {
            $error = $_GET['error'];
            print "<font color='red'><b>$error</font></b><br>";
            
      }
      if($picker == '' || $supervisor == '')
      {
            print "<font color='red'><b>Supervisor and picker names are required.</font></b><br>";
            exit();
      }
      ?>
      
      <table>
      <tr>
      <td><big>Supervisor:</b></td><td><big><?php echo $supervisor; ?></td></tr>
      <tr><td><big>Picker: </b></td><td><big><?php echo $picker ?></td>
      </tr></table>

      <br><b>Enter a new order to this pick list below:<br></b>
      <form action='results.php' method='post' name='order'>
      <table>
      <tr><td><center><b>Movement Order</b></td><td><b>Hot</b></td>
      </tr>
      <tr>
      <td><input type='text' name='order_num' onKeyPress="checkEnter(event)"> </td>
      <td><input type='checkbox' name='hot'></td>
      
      <input type='hidden' name='supervisor' value='<?php echo $supervisor; ?>'>
      <input type='hidden' name='picker' value='<?php echo $picker; ?>'>
      <input type='hidden' name='list_id' value='<?php echo $line['pick_list_id']; ?>'>
      <td colspan='10'><center><input type='submit' class='bn' value='Save' name='new_pick'></td></tr>
      </table>
      </form>
      <?php

      
      $qpick = "SELECT * FROM orders WHERE picker = '$picker' AND qa = '0' AND inv_issue='0'
      AND packed='0' AND xship='0' AND ship_confirm='0' AND xship_issue='0'";

      $rpick = mysql_query($qpick) or die(mysql_error());
      if(mysql_numrows($rpick) != '0')
      {
            ?>
            <br><b>Below is the current/active pick list for this picker:<br>
            <table>
            <tr><td><center><b>Movement Order</b></td><td><b>Hot</b></td>
            </tr>
            <?php

            for($i=0;$i<mysql_numrows($rpick);$i++)
            {
                  $pick_list = mysql_fetch_array($rpick);
                  ?>
                  <form action='results.php' method='post'>
            
                  <tr>
             <td><input type='text' name='order_num' value='<?php echo $pick_list['order_num']; ?>'></td>
                  <?php
                  if($pick_list['hot'] == '1')
                  {print"<td><input type='checkbox' name='hot' checked='checked'></td>";}
                  else
                  {print"<td><input type='checkbox' name='hot'></td>";}
                  ?>
                  
                  <input type='hidden' name='org_order_num' value='<?php echo $pick_list['order_num'] ?>'>      
                  <input type='hidden' name='list_id' value='<?php echo $pick_list['pick_list_id'] ?>'>      
                  <input type='hidden' name='picker' value='<?php echo $pick_list['picker'] ?>'>
      
                  <td colspan='10'><center><input type='submit' class='bn' value='Edit' name='change'></td></tr>
                  
                  </form>
                  <?php
            }
            print "</table>";

            ?>
      <br>To transfer this pick list to another picker, scan the name below and click transfer.<br>
      <form action='results.php' method='post'>
      <input type='text' name='new_picker'>      
      <input type='hidden' name='list_id' value='<?php echo $pick_list['pick_list_id'] ?>'>      
      <input type='submit' name='transfer' value='Transfer'>
      </form>
      <?php
      }      
}
include 'include/footer.include';

Any help would be appreciated.

Thank you!