JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>

<body>

  <button onclick="CreateValues()">Click me</button>
  <p id="demo"></p>

  <script>
    function CreateValues() {
      var demo = document.getElementById("demo");
      demo.innerHTML = "";
      var values = ["1,000,000.14", "1000000,14", "1000000.14", "1000,100.14", "1000000", "1,000,000,000", "1,000,000,000.14"];

      for (index = 0; index < values.length; ++index) {
        TranslateValues(values[index]);
      }
    }

    function TranslateValues(item) {

      //If Splitting is anything other then 2, it gets used as a thousand seperator or does not get used at all. In this Scenario, we check for 2 decimal places
      var Splitting = item.indexOf(",") != -1 ? item.split(',')[1].length : 0;
      var newItem = Splitting == 2 ? item.replace(/,/g, ".") : item.replace(/,/g, "");

      var demo = document.getElementById("demo");
      demo.innerHTML = demo.innerHTML + "Old item: " + item + "<br /> New item: " + parseFloat(newItem).toFixed(2) + "<br /><br />";
    }

  </script>

</body>