JSFiddle - React, Tailwind, and code Playground

by alirokni

HTML

<div id="t">
  test
</div>

JavaScript

var str = "a,b,a,d,a";
var res = '';
for (var i = 0; i < str.length; i++) {
  res += str[i]+str[i+1];
}

document.querySelector('#t').innerHTML = res;