Answers for "Pastying strings to the clipboard using pure Javascript"

js copy text to clipboard

function copy() {
  var copyText = document.querySelector("#input");
  copyText.select();
  document.execCommand("copy");
}

document.querySelector("#copy").addEventListener("click", copy);

js copy string to clipboard

const el = document.createElement('textarea');
el.value = str;	//str is your string to copy
document.body.appendChild(el);
el.select();
document.execCommand('copy');	// Copy command
document.body.removeChild(el);