JSFiddle - React, Tailwind, and code Playground

HTML

<span data-hello="a">a</span>
<span data-hello="b">b</span>
<span data-hello="c">c</span>

JavaScript

var dataElems = document.querySelectorAll("[data-hello]")
for (var i=0;i<dataElems.length;i++) { 
    dataElems[i].onclick = function(i,v) {
        alert(this.innerHTML+ '>>>>>>' +this.getAttribute("data-hello"))        
    }
}