JSFiddle - React, Tailwind, and code Playground

HTML

<div id="first" contenteditable>My content is editable.</div>
<div id="second">Mine isn't.</div>
<div id="third">Mine either right now, but it will when the script runs.</div>
These elements have editable contents: <span id="output"></span>

JavaScript

document.getElementById("third").contentEditable = true;

var contEditables = document.querySelectorAll("[contenteditable]"),
    output = [], i = 0;
for (; i < contEditables.length; i++)
    output.push("#" + contEditables[i].id);
document.getElementById("output").innerHTML = output.join(", ");