$(document).ready(function(){
  var id = $("select[name=service_type]").val();
  if (id == '92' || id == '90') {
    $("select[name=packaging_type]").val('01'); // Your Packaging  
  } else {
    // change this to whatever your default package type will be
    $("select[name=packaging_type]").val('06'); // FedEx Envelope
  }
  $("select[name=service_type]").change( function() {
    var id = $("select[name=service_type]").val();
    if (id == '92' || id == '90') {
      $("select[name=packaging_type]").val('01');  
    } else {
      $("select[name=packaging_type]").val('06');
    }
  });
  
  $('form[name="ship_fedex"]').submit(function() {
    if ($('[name=rate_request]').is(':checked')) {
      // post to rate_request page
      var orders_id = $.getUrlVar('oID');
      $.post("rate_fedex.php", $("[name=ship_fedex]").serialize() + '&orders_id=' + orders_id, function(data) {
        jAlert(data);
      });
      return false; // do not submit the form
    } else {
      return true; // submit the form as normal
    } 
  });
});