JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Input:</h1>

<div id="input">
    
    <h2>Headline</h2>

    <p>
        Lorem ipsum dolor sit <strong>amet, consetetur</strong> sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut <em>abore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam <a href="#">et justo duo</a> dolores et ea</em> rebum.
        Lorem ipsum dolor sit <strong>amet, consetetur</strong> sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut <em>abore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam <a href="#">et justo duo</a> dolores et ea</em> rebum.
    </p>
    
</div>

<p>
    Remove tags:
    <input name="tag" placeholder="Example: strong" value="strong" />
    <input name="button" type="button" value="Remove" />
</p>

<h1>Output:</h1>

<div id="output">
    
</div>

CSS

body { font-family: sans-serif; }
#input { background-color:#ABABAB; padding: 30px; }
#output { background-color:#BABABA; padding: 30px; }

JavaScript

function removeTag ( str, tag ) {
    var r = new RegExp('<\s*/?\s*' + tag + '.*?>','gi');
    if(str.search(r) != -1) {
        var clean = str.replace(r, '');
        return clean;
    } else {
        // tag einfĂĽgen
    }
}

$('input[name="button"]').click(function() {
    var str = removeTag($('#input').html(),$('input[name="tag"]').val());
    $('#output').html(str);  
});