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JavaScript

Posted by Tani Huang
Tani Huang
6,952 Points

Can Someone explain this in detail..please (var or let inside addEventListener or outside addEventListener)

<div class="container">
 <h1>Welcome</h1>
 <p>Hello welcome to my page.</p>
 <ul class="list reset">
  <li>a</li>
  <li>b</li>
  <li>c</li>
  <li>d</li>
  <li>e</li>
 </ul>
 <button class="btn">Start</button>
</div>

var btn = document.querySelector(".btn");

btn.addEventListener('click', () => {
  var ul = document.getElementsByTagName('ul')[0];
  var li = document.querySelector('li:last-child');
  ul.removeChild(li);
})

var btn = document.querySelector(".btn");
var ul = document.getElementsByTagName('ul')[0];
var li = document.querySelector('li:last-child');

btn.addEventListener('click', () => {
  ul.removeChild(li);
})

Why the second one only works once
Why the first one can keep removing

1 Answer

Steven Parker
Steven Parker
229,744 Points
Steven Parker
Steven Parker
229,744 Points

The first example gets a new "li" each time you click, so it will always remove the last item.

The second one only sets "li" once, when the program first loads. So once you click and remove it, it never gets updated to select any of the remaining items.