JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" />
<input type="text" />
<input type="text" />
<input type="text" />

JavaScript

var inputs = document.getElementsByTagName('input');

for (var i = 0; i < inputs.length; i++)
    inputs[i].onblur = functionHandler;

function functionHandler() {
    if(this.value == "") {
        alert('empty');
    }        
}