JSFiddle - React, Tailwind, and code Playground

HTML

<div class="radio" style="float:left; width: 100%;">
      <label><input type="radio" class="a" onclick="startUp();" name="optradio">Option 1</label>
    </div>
    <div class="radio">
      <label><input type="radio" class="a" onclick="startUp();" name="optradio">Option 2</label>
    </div>
    <div class="radio">
      <label><input type="radio" id="radio2" class="a" onclick="startUp();" name="optradio">Option 3</label>
    </div>

JavaScript

function startUp() {
    alert("alert first");
    sub();
}

function sub() {
    var drop = document.getElementsByClassName('a');
    for(let i=0;i<drop.length;i++){
        drop[i].addEventListener('click', function(){
          alert("all other");
        });
    };
}