how to get copy button in html code example

Example: copy to clipboard javascript

// Since Async Clipboard API is not supported for all browser!
function copyTextToClipboard(text) {
  var textArea = document.createElement("textarea");
  textArea.value = text
  document.body.appendChild(textArea);
  textArea.focus();
  textArea.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');
  }

  document.body.removeChild(textArea);
}