JSFiddle - React, Tailwind, and code Playground

HTML

<div>0</div>
<div>1</div>
<div>2</div>
<div>3</div>
<div>4</div>

CSS

div{
    height: 20px;
    margin: 5px;
    background: orange;
}

JavaScript

var divs = document.getElementsByTagName('div');

for(var i = 0; i < divs.length; i++){
     var ele = divs[i];
  
    /**wrong
    ele.onclick = function(){
        alert(i);
    }
    */
    
    /**right**/
    ele.onclick = (function(index){
        return function(){
            alert(i +' '+ index);
        }
    })(i);
}