1. Open the webChatUI.js file.
2. Replace the "getTopic" function with that from the sample version.
3. Add the "isTopicValid" function into your version.
4. Open the customerJourney.js file.
5. Replace the "sanitiseTopic" function with that from the sample version.
6. Open the webChatLogon.js file.
7. Add the following block into the gatherDetails function:
    var topicValid = chatUI.isTopicValid();
    if (!topicValid) {
        errors += "The topic field is invalid\n";
    }