Cannot customize radio type in form.md with a new form-only.js javascript file

I want to make javascript available for form.md pages. This is what I have done so far:

1. File: /user/themes/antimatter/templates/form.html.twig
   Comment: I added two new javascript files

{% extends 'partials/base.html.twig' %}

{% block content %}

{% block javascripts %}
{{ parent() }}
{% do assets.add('theme://js/utilities.js') %}
{% do assets.add('theme://js/form-only.js') %}
{% endblock %}
{{ assets.js() }}

{{ content }}
{% include "forms/form.html.twig" %}

{% endblock %}

1. File: /user/themes/antimatter/js/utilities.js
   // Helper function to add an event listener
   function addEvent (el, event, callback) {
   if ('addEventListener' in el) { // If addEventListener works
   el.addEventListener(event, callback, false); // Use it
   } else { // Otherwise
   el['e' + event + callback] = callback; // CreateIE fallback
   el[event + callback] = function () {
   el'e' + event + callback;
   };
   el.attachEvent('on' + event, el[event + callback]);
   }
   }

// Helper function to remove an event listener
function removeEvent(el, event, callback) {
if ('removeEventListener' in el) { // If removeEventListener works
el.removeEventListener(event, callback, false); // Use it
} else { // Otherwise
el.detachEvent('on' + event, el[event + callback]); // Create IE fallback
el[event + callback] = null;
el['e' + event + callback] = null;
}
}

1. File: /user/themes/antimatter/js/form-only.js
   (function() {
   var form, options, other, otherText, hide; // Declare variables
   form = document.getElementById('my-survey-form'); // Get the form
   options = form.elements.Cq8; // Get the radio buttons
   other = document.getElementById('other'); // Other radio button
   otherText = document.getElementById('other-text'); // Other text input
   otherText.className = 'hide'; // Hide other text input

   for (var i = [0]; i < options.length; i++) { // Loop through radios
   addEvent(options[i], 'click', radioChanged); // Add event listener
   }

   function radioChanged() {
   hide = other.checked ? '' : 'hide'; // Is other checked?
   otherText.className = hide; // Text input visibility
   if (hide) { // If text input hidden
   otherText.value = ''; // Empty its contents
   }
   }
   }());

Finally my form page is

1. File: /user/pages/05.survey-form/form.md

   YAMLCopy

   
   title: 'Survey Form'
   form:
   name: my-survey-form
   fields:
               -
           name: Cq8
           type: radio
           label: 8. Single File Size Limit                 
           options:
               1: Unlimited
               2: 10 GB
               3: 15 GB
               4: 4 TB
               other: Other                              
           validate:
               required: false
       -
           name: other-text
           type: text
           label: Other             
   
   buttons:
       -
           type: submit
           value: Submit
   
   process:
       -
           advise:
       -
           message: 'Your recommendation is coming'
       -
           display: recommendation
   

# Sync and Share

Final Comment: Cannot get radio type in form.md work with form-only.js 
It's not working at all. Nothing about javascript. Do I need to edit anything else?