JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <ul>

    </ul>
</div>
<textarea></textarea>
<button>Send</button>

CSS

div{
	overflow-y: scroll;
	overflow-x: hidden;
	height: 400px; 
  width:400px;
  border:1px solid black;
}
div ul {
	list-style: none;
}
div ul li{
  float:left;
  clear:left;
	background-color: #b70505;
  color: white;
  font-weight: 600;
  font-size: 0.8em;
  border-radius: 25px;
  margin-top: 5px;
  padding: 10px;
  max-width:200px;
  word-wrap:break-word;
}

JavaScript

var box = document.getElementsByTagName('div')[0];
var newText = document.getElementsByTagName('textarea')[0];
var button = document.getElementsByTagName('button')[0];

button.addEventListener('click', function(e){
		e.preventDefault();
		if(newText.value !== ''){
			var Newitem = document.createElement('li');
      Newitem.innerHTML = newText.value;
			box.getElementsByTagName('ul')[0].appendChild(Newitem);
			box.scrollTop = box.scrollHeight;
		}
});