JSFiddle - React, Tailwind, and code Playground

HTML

<a href="javascript:" class="red-btn">red</a>
<a href="javascript:" class="green-btn">green</a>

<!-- Result -->
<div class="red" >Testing Text1</div>
<div class="red" >Testing Text2</div>

CSS

.red {
		    color: red;
		 
}
.green {
		    color: green;
		    
}

JavaScript

jQuery(document).ready(function(){
		jQuery(document).on('click',".red-btn",function (){
		    alert("red color");
				                        jQuery(".green").removeClass("green").addClass("red");
			});
    
		jQuery(document).on('click',".green-btn",function (){
		alert("green color");
				jQuery(".red").removeClass("red").addClass("green");
			});
		});