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() {show(b);};

a.onblur = function() {
    setTimeout(function() {
        if(document.activeElement !== b && document.activeElement !== a){
            hide(b);
        }
            }, 0);
};

b.onblur = a.onblur;