JSFiddle - React, Tailwind, and code Playground

HTML

<div id="display">

</div>
<button onClick="imageswap()">GO</button>

JavaScript

var a = 0;

function imageswap() {
alert(a);
  if (a == 0) {
    document.getElementById('display').innerHTML = 'RED';
     a += 1;
  } else if (a == 1) {
    document.getElementById('display').innerHTML = 'YELLOW';
     a += 1;
  } else {
    document.getElementById('display').innerHTML = 'GREEN';
     a = 0;
  }
}