JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text"/>
<textarea></textarea>
<div> 123 </div>

JavaScript

var handler = function(tagName) {
    // You Now get the tagName, do something with it.
    alert(tagName);
};

document.onmousedown = function(evt) {
    evt = evt || window.event;
    console.log(evt);
    var target = evt.target || evt.srcElement;
    var tagName = target.nodeName.toLowerCase();
    if (tagName == "input" || tagName == "textarea") {
        handler(tagName);
    } else {
        return "nothing";
    }
};