JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<textarea name='codearea1' id='codearea1' rows="7" cols="50">Suspendisse convallis, metus at laoreet congue, sapien dui ornare magna, a porttitor felis purus a ipsum. Morbi vulputate erat rhoncus, luctus neque ut, lacinia orci. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis
  egestas. Fusce aliquam, nulla nec fringilla ultrices, ipsum lectus maximus nisl, ut laoreet purus lectus eget nisl. Duis blandit cursus nulla. Vestibulum consectetur, nunc non viverra condimentum, neque neque tincidunt diam, nec vestibulum neque nisi
  ac sem. Integer aliquam a leo id laoreet. Mauris ultrices mauris lorem, eu hendrerit odio volutpat ut. Nam eget hendrerit metus.</textarea>
  
  <div id='n101'>n101 button</div>
<div id='n102'>n102 button</div>

JavaScript

var isChrome = !!window.chrome && !!window.chrome.webstore;
var text = 'text1';

jQuery("#n101").on("click", function() {
  if (isChrome) {
    var val = jQuery("#codearea1").val();
  } else {

    jQuery("#codearea1").focus();
    var val = jQuery("#codearea1").val();
    document.execCommand('insertText', false, text);
  }
});

var isChrome = !!window.chrome && !!window.chrome.webstore;
var text = 'text2';

jQuery("#n102").on("click", function() {
  if (isChrome) {
    var val = jQuery("#codearea1").val();
  } else {

    jQuery("#codearea1").focus();
    var val = jQuery("#codearea1").val();
    document.execCommand('insertText', false, text);
  }
});