JSFiddle - React, Tailwind, and code Playground

by Gaius Martius

HTML

<input id="increment" name="plus" type="button" value="+"> 
<p class="count">1</p>
<p class="count">1</p>
<p class="count">1</p>
<p class="count">1</p>
<p class="count">1</p>
<p class="count">1</p>

JavaScript

var elem = document.getElementsByClassName('count'),
	  num = +elem[0].innerHTML;
if (document.getElementsByClassName('count')) {
 
  document.getElementById('increment').onclick = function addNum() {
     num += 1;
     for (var i = 0; i < elem.length; i++) {
        elem[i].innerHTML = num;
				console.log(elem[i].innerHTML);
      }
  }
}