How to copy text to clipboard from popup.js chrome extension clipboard?

Question

JavaScript

https://jsbin.com/mayenevubi/edit?html , js tried
this way but throws Discontiguous selection is not supported.
here is the manifest

"permissions": [
    "webNavigation",
    "notifications",
    "tabs",
      "storage",
    "clipboardRead",
    "clipboardWrite"
  ],

Answer 1

<textarea class="js-copytextarea">Hello I'm so11111me text</textarea>

var copyTextareaBtn = document.querySelector('.js-textareacopybtn');

copyTextareaBtn.addEventListener('click', function(event) {
  var copyTextarea = document.querySelector('.js-copytextarea');
  copyTextarea.select();

  try {
    var successful = document.execCommand('copy');
    var msg = successful ? 'successful' : 'unsuccessful';
    console.log('Copying text command was ' + msg);
  } catch (err) {
    console.log('Oops, unable to copy');
  }
});

on click launch this function