JSFiddle - React, Tailwind, and code Playground
HTML
<div id='1'>1</div>
<div id='2'>2</div>
<div id='3'>3</div>
<div id='4'>4</div>
<div id='5'>5</div>
CSS
div{
background-color: grey;
}
JavaScript
var div = document.getElementsByTagName('div');
var size = div.length;
function changeColor(){
this.style.backgroundColor = '#27f';
}
for( var i = 0; i < size; i++ ){
div[i].onclick = changeColor;
}