Копировать в буфер

<!DOCTYPE html>
<html>
<body>

<p>Click on the button to copy the text from the text field. Try to paste the text (e.g. ctrl+v) afterwards in a different window, to see the effect.</p>

<input type="text" value="Hello World" id="myInput">
<button onclick="myFunction()">Copy text</button>

<script>
function myFunction() {
  // Get the text field
  var copyText = document.getElementById("myInput");

  // Select the text field
  copyText.select();
  copyText.setSelectionRange(0, 99999); // For mobile devices

  // Copy the text inside the text field
  navigator.clipboard.writeText(copyText.value);

  // Alert the copied text
  alert("Copied the text: " + copyText.value);
}
</script>

</body>
</html>