I want to make a panel with a text box and a button to execute and another to delete and another to copy from the clipboard

function createPanel() {
  var panel = (function() {
    var elem = document.createElement('div');
    elem.style.backgroundColor = '#ff0';
    var input = document.createElement('input');
    var btExec = document.createElement('button');
    var btDel = document.createElement('button');
    var btCopy = document.createElement('button');
    btExec.innerText = 'Execute';
    btDel.innerText = 'Delete';
    btCopy.innerText = 'Copy';
    elem.appendChild(input);
    elem.appendChild(btExec);
    elem.appendChild(btDel);
    elem.appendChild(btCopy);
    return elem;
  })();
  document.body.appendChild(panel);
}

function main() {
  createPanel();
}

main();