如何知道点击时选择了多少类元素？

document.getElementById('targetElement').addEventListener('click', function(event) {
  var selectedElements = document.querySelectorAll('.selected');
  console.log('选择了' + selectedElements.length + '个元素');
});

$('#targetElement').click(function() {
  var selectedElements = $('.selected');
  console.log('选择了' + selectedElements.length + '个元素');
});

<style>
  .selected {
    background-color: yellow;
  }
</style>

<div id="targetElement">
  <div class="selected">元素1</div>
  <div>元素2</div>
  <div class="selected">元素3</div>
</div>

<script>
  document.getElementById('targetElement').addEventListener('click', function(event) {
    var selectedElements = document.getElementsByClassName('selected');
    console.log('选择了' + selectedElements.length + '个元素');
  });
</script>