JSFiddle - React, Tailwind, and code Playground

HTML

<div id="text"></div>

CSS

#text {
    display: block;
    border: 1px solid #bfbfbf;
    height: 200px;
    width: 300px;
}

#text span {
    background: #bada55;
}

JavaScript

$("#text").prop("contenteditable", true);
var string = $("#text")[0].innerHTML;
$("#text").innerHTML = string.replace("design", "<span>design</span>");