JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">
<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap-theme.min.css">
<script src="http://netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<a href="#" id="LINK1">Skopiuj “WAR1” do schowka</a>
<br>
<a href="#" id="LINK2">Skopiuj “WAR2” do schowka</a>
<br>
<textarea placeholder="Testuj tutaj..."></textarea>

JavaScript

function KopiujDoSchowka(value) {
  var tempInput = document.createElement("input");
  tempInput.value = value;
  document.body.appendChild(tempInput);
  tempInput.select();
  document.execCommand("copy");
  document.body.removeChild(tempInput);
  alert('Skopiowano');
}

document.querySelector('#LINK1').onclick = function() {
  KopiujDoSchowka('WAR1');
}

document.querySelector('#LINK2').onclick = function() {
  KopiujDoSchowka('WAR2');
}