cant get checked value out of input checkbox javascript code example

Example 1: how to take value only from the checked checkbox

document.getElementById('select').onclick = function() {
  var checkboxes = document.querySelectorAll('input[type="checkbox"]:checked');
  for (var checkbox of checkboxes) {
    document.body.append(checkbox.value + ' ');
  }
}

Example 2: how to take value only from the checked checkbox

$(document).ready(function() {
  $('#select').click(function() {
    $('input[type="checkbox"]:checked').each(function() {      // $(':checkbox:checked')
      document.body.append(this.value + ' ');                  // $(this).val()
    });
  });
});