JSFiddle - React, Tailwind, and code Playground

HTML

<input id="a" value="a" />
<input id="b" value="b" />

<div class="console"></div>

CSS

#b {display:none;}

JavaScript

var a = document.getElementById("a");
var b = document.getElementById("b");

function show(elem) {
    elem.style.display = 'inline-block';
}

function hide(elem) {
    elem.style.display = 'none';
}

a.onfocus = function() {
    console.log('focus a fired');
    show(b);   
};

var hideB = function(){
    console.log(this.id, ': blur fired');
    hide(b);
};

a.onblur = hideB;
b.onblur = hideB;

b.onfocus = function(){
    console.log('focus b fired');
    show(b);   
};