js 获取ul 下面所有li

<ul id="myList">
  <li>Item 1</li>
  <li>Item 2</li>
  <li>Item 3</li>
</ul>

var listItems = document.getElementsByTagName('li');
for (var i = 0; i < listItems.length; i++) {
  console.log(listItems[i].textContent);
}

var listItems = document.querySelectorAll('#myList li');
listItems.forEach(function(item) {
  console.log(item.textContent);
});

<ul id="myList">
  <li class="item">Item 1</li>
  <li class="item">Item 2</li>
  <li class="item">Item 3</li>
</ul>

var listItems = document.getElementsByClassName('item');
for (var i = 0; i < listItems.length; i++) {
  console.log(listItems[i].textContent);
}

window.onload = function() {
  var listItems = document.querySelectorAll('#myList li');
  listItems.forEach(function(item) {
    console.log(item.textContent);
  });
};