JSFiddle - React, Tailwind, and code Playground

HTML

Reference: <br>
<span class=hello>Hello</span> <span class=world>World</span>, 
<span class=john>John</span> <span>Doe</span><br>

<br>Result: <br>
<span id=result></span>

JavaScript

let result = document.getElementById('result'),
		hello = document.querySelector('.hello'),
    world = document.querySelectorAll('.world')[0],
    john = document.getElementsByClassName('john')[0],
    doe = document.getElementsByTagName('span')[3]
    

result.innerHTML = 
		hello.innerHTML+` ${world.innerHTML}, ${john.innerHTML} `+doe.innerHTML