JSFiddle - React, Tailwind, and code Playground

HTML

<textarea name="" id="source" cols="30" rows="10">Quam temere in vitiis, legem sancimus haerentia.</textarea>
<br><br><br>
<textarea name="" id="myText" cols="30" rows="10"></textarea>

JavaScript

function strReplace() {
  var myStr = document.getElementById("source").value;
  var newStr = myStr
    .replace(/&‌#‌1084‌;/g, "м")
    .replace(/&‌quot‌;/g, "&quot;");

  if (document.getElementById("source").value == "") {
    alert("Textarea is empty!");
  } else {
    document.getElementById("myText").innerHTML = newStr;
    //document.getElementById("source").select();
    //document.getElementById("source").value = "";
  }
}

strReplace();