JSFiddle - React, Tailwind, and code Playground

HTML

<div class='conlabel'>Have you started trading yet?</div>
      <table width="100">
              <tr>
                <td><label>
                  <input type="radio" name="example" value="Yes" id="example_0" required />
                  Yes</label></td>
          </tr>
          <tr>
            <td><label>
              <input type="radio" name="example" value="No" id="example_1" required />
              No</label></td>
          </tr>
</table><br>
  <li>
      <div class='conlabel'>If Yes, enter trading name:</div>
          <input type="text" id="field1" name="field1" placeholder="" disabled />
  </li><br>
  <li>
      <div class='conlabel'>If No, then:</div>
          <input type="text" id="field2" name="field2" placeholder="" disabled />
  </li><br>

<li>
      <div class='conlabel'>Enter trading start date (enabled when started trading yet = yes + trading name = notnull:</div>
          <input type="text" id="field3" name="field3" placeholder="" disabled />
  </li><br>

JavaScript

$(function(){
    $("#example_0, #example_1").change(function(){
        $("#field1, #field2").val("").attr("disabled",true);
        if($("#example_0").is(":checked")){
            $("#field1").removeAttr("disabled");
            $("#field1").focus();
        }
        else if($("#example_1").is(":checked")){
            $("#field2").removeAttr("disabled");
            $("#field2").focus();   
        }
    });
});