Populate a field based on another field's content in Jira server

[Ops]

Hi All! I have tried Atlassian Support with this question but they have suggested I ask the community as this is a customization.

I would like a field to display based on the value of a radio button field. Think of it like this: Field A (radio button) - "More info required: Yes/No". Field B (free text) - "Enter more information". Field B will display if Field A is "Yes" but will be hidden if it is "No"

I have followed the script provided in this KB and I can get the script working where Field A is a drop down. See my commented code to help me understand how it works:

<script type="text/javascript">
  // Set the query field to lookup the value of here
  query = document.getElementById('customfield_10000');
  if (query) {
    // Set the target field to show or hide based on the query field here
    target = document.getElementById('customfield_14282');
 
    // Hide the target field unless the query value already matches
    // what you want it to be
    if (query.value != 17830) target.style.display='none';

    // On change, show the target field if query value matches
    // what you want it to be else hide it
    query.onchange=function() {
      if (this.value == 17830) { 
        target.style.display=''; 
        // Show some placeholder text, if you want
        // target.value="Enter something here!";
      } else {
        target.style.display='none';
      }
    }
  }
</script>

Can any one assist with a way to read the value of a radio button field? They seem to respond differently to a drop down.

Many thanks,

Matthew