JSFiddle - React, Tailwind, and code Playground
HTML
<div>div 1</div>
<div id="hi">
<span style="border:1px solid red;">This span should stay</span>
<br />
this should be removed
</div>
<div>div 3</div>
JavaScript
$(document).ready(function(){
$('body').children().not($('span').parents()).empty();
$('#hi').contents().filter(function(){
return this.localName !== 'span'
}).remove();
});