JSFiddle - React, Tailwind, and code Playground

HTML

<div class="textniz">
  <textarea class="one" id="myInput1" name="myInput1" data-ta="myInput1" readonly>
One
One
One</textarea>
</div>

<div class="textniz">
  <textarea class="two" id="myInput2" name="myInput2" data-ta="myInput2" readonly>
Two
Two
Two</textarea>
</div>

<div class="textniz">
  <textarea class="three" id="myInput3" name="myInput3" data-ta="myInput3" readonly>
Three
Three
Three</textarea>
</div>


<div class="navbar">
  <div class="container">
    <a class="logo" href=".//templates/chat.html">test</a>
  </div>
</div>

<div>
  <button class="menu">menu</button>

  <button class="image">image</button>

  <button onclick="show(this.dataset.ta)" class="en" data-ta="myInput1">textarea1</button>
  <button onclick="show(this.dataset.ta)" class="gr" data-ta="myInput2">textarea2</button>
  <button onclick="show(this.dataset.ta)" class="ru" data-ta="myInput3">textarea3</button>

  <button onclick="Copytextfunction(this.dataset.ta)" class="menucopy" data-ta="myInput1">copy1</button>
  <button onclick="Copytextfunction(this.dataset.ta)" class="menucopy" data-ta="myInput2">copy2</button>
  <button onclick="Copytextfunction(this.dataset.ta)" class="menucopy" data-ta="myInput3">copy3</button>
</div>

CSS

textarea[data-ta], /* hide textareas */
.menucopy[data-ta] /* hide copy buttons */
{
  display: none;
}

body[show="myInput1"] [data-ta="myInput1"],
body[show="myInput2"] [data-ta="myInput2"],
body[show="myInput3"] [data-ta="myInput3"]
{
  display: initial;
}

JavaScript

let taId;
try
{
  taId = localStorage.getItem("taId"); //get stored id
}
catch(e){}

if (!document.getElementById(taId))
  taId = document.querySelector(".textniz textarea").id; //fallback to default first textarea

show(taId); //show text area

function show(taId) {
  document.body.setAttribute("show", taId);
  try
  {
    localStorage.setItem("taId", taId); //store textarea id
  }
  catch(e){}
}

function Copytextfunction(taId)
{
  var value = document.getElementById(taId).value;
  var copyText = document.createElement("textarea");
  copyText.value = value;
  copyText.style.position = "fixed";
  copyText.style.top = "-1000vh";
  document.body.append(copyText)
  copyText.select();
  copyText.setSelectionRange(0, 99999)
  document.execCommand("copy");
  console.log(value)
  copyText.remove()
}