JSFiddle - React, Tailwind, and code Playground

HTML

<textarea id="unsafe_html"></textarea>
<textarea id="sanitized_html"></textarea>
<div id="sanitized_elements" style="border: red"></div>

CSS

div,
textarea {
    display: block;
    width: 100%;
    height: 100px;
}

JavaScript

/**
 * Copyright (c) 2010 by Gabriel Birke
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the 'Software'), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

function Sanitize(){
  var i, e, options;
  options = arguments[0] || {};
  this.config = {};
  this.config.elements = options.elements ? options.elements : [];
  this.config.attributes = options.attributes ? options.attributes : {};
  this.config.attributes[Sanitize.ALL] = this.config.attributes[Sanitize.ALL] ? this.config.attributes[Sanitize.ALL] : [];
  this.config.allow_comments = options.allow_comments ? options.allow_comments : false;
  this.allowed_elements = {};
  this.config.protocols = options.protocols ? options.protocols : {};
  this.config.add_attributes = options.add_attributes ? options.add_attributes  : {};
  this.dom = options.dom ? options.dom : document;
  for(i=0;i<this.config.elements.length;i++) {
    this.allowed_elements[this.config.elements[i]] = true;
  }
  this.config.remove_element_contents = {};
  this.config.remove_all_contents =...