JSFiddle - React, Tailwind, and code Playground

HTML

<div id='aoeu'>
    Ammonium NH%4^+ <br/>
    Copper(I) Cu^+ <br >
    Gold(I) Au^+ <br>
    Rubidium Rb^+ <br />
    Acetone CH%3COCH%3 <br />
    Glycerin C%3H%5(OH)%3 <br>
</div>

JavaScript

var el = document.getElementById("aoeu"),
    content = el.innerHTML.replace(/^\s+|\s*(<br *\/?>)?\s*$/g,""),
    lines = content.split(/\s*<br ?\/?>\s*/);

console.dir(lines);