JSFiddle - React, Tailwind, and code Playground

HTML

<div class="oneclass">
<span class="book"> мой блок </span>
</div>

CSS

.oneclass{
  height: 30px; 
  width:300px;
  background: grey;
}

JavaScript

$('.oneclass').click(function(){
$(this).children('span').remove();
if(!$(this).hasClass('newclass')) {
	$(this).addClass('newclass');
}
else if($(this).hasClass('newclass')) {
	$(this).append( "<p>Test</p>" );
}
});