JSFiddle - React, Tailwind, and code Playground

HTML

<div style="background-color:red"></div>
<div style="background-color:green"></div>
<div style="background-color:blue"></div>
<div style="background-color:yellow"></div>


<button id="btn">
Do the thing
</button>

JavaScript

(function() {
  	document.getElementById('btn').addEventListener('click', function(e) {
      e.preventDefault();
      getDivs();
  	})
  })()
  
  function getDivs() {
    var elements = document.getElementsByTagName('div');
		console.log(elements);
    for (var i = 0; i < elements.length; i++) { 
    	elements[i].innerHTML = "sometext" + i;
    }
  }