JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

.readOnly{
    background-color: #F6F6F6;
}

JavaScript

var a='<p style="font-size: 18px;">sadasdasdsasdasda<span style="background-color: rgb(0, 255, 0);" data-mce-style="background-color: #00ff00;">sdasdasda</span><span style="background-color: rgb(255, 0, 0);" data-mce-style="background-color: #ff0000;"><span style="background-color: rgb(0, 255, 0);">sdasd</span>asdasdasdas</span>dasdasd</p>';
var outer=$(a);
outer.find("*").css('background-color','transparent');
$("div").append(outer);