As was pointed out in a response to a recent post I made, you have to be aware that either

• you have control over the clients running the script to ensure that the local scripting language is always running,
  or,
• you need to take into account that users can modify the client config to disable scripting locally and/or muck around with your form to send invalid data

As an aside, you may want to consider skipping the form entirely for the "else" condition. Procedurally, I can understand the logic in having all users flowing through the same pages/forms, however, you obviously have all the data needed to skip the form entirely and send them to the next stage.