JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//knockoutjs.com/downloads/knockout-3.4.0.js"></script>
<button data-bind="click:ev">asdf</button>


<div data-bind="click:ev">balabal</div>
<div  data-bind="click:ev" >Write something here</div>

CSS

div{
  background-color: red;
  border: solid 1px black;
  width: 100px;
  height: 100px;
}

JavaScript

ko.applyBindings({
	ev: function(){
  	console.log('test')
  }
}, document.body)