Baduymda

<textarea id="source"></textarea>
<button id="action">Run</button>
<iframe id="destination"></iframe>
<script>
  var source = document.getElementById("source");
  var destination = document.getElementById("destination");
  var button = document.getElementById("action");
  button.addEventListener("click", run, false);
  function run() {
    var d = destination.contentDocument;
    d.open();
    d.write(source.value);
    d.close();
  }
</script>

thanks