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JavaScript JavaScript and the DOM (Retiring) Traversing the DOM Solution: Using nextElementSibling

Mel Parker
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.a{fill-rule:evenodd;}techdegree
Mel Parker
Front End Web Development Techdegree Student 7,932 Points
Posted by Mel Parker
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Mel Parker
Front End Web Development Techdegree Student 7,932 Points

I can't get the javascript for the "up" and "down" buttons to work. I followed the code in the video.

const toggleList = document.getElementById('toggleList');
const listDiv = document.querySelector('.list');
const descriptionInput = document.querySelector('input.description');
const descriptionP = document.querySelector('p.description');
const descriptionButton = document.querySelector('button.description');
const listUL = listDiv.querySelector('ul');
const addItemInput = document.querySelector('input.addItemInput');
const addItemButton = document.querySelector('button.addItemButton');

listUL.addEventListener('click', (event) => {
 if (event.target.tagName == 'BUTTON') {
   if (event.target.className == 'remove') {
    let li = event.target.parentNode;
    let ul = li.parentNode;
    ul.removeChild(li);
  } 
   if (event.target.className == 'up') {
    let li = event.target.parentNode;
    let prevLi = li.previousElementSibling;
    let ul = li.parentNode;
    if (prevLi) {
      ul.inserBefore(li, prevLi);
   }
  }
   if (event.target.className == 'down') {
    let li = event.target.parentNode;
    let nextLi = li.nextElementSibling;
    let ul = li.parentNode;
    if (nextLi) {
      ul.inserBefore(nextLi, li);
   }
  }  
 }
});


toggleList.addEventListener('click', () => {
  if (listDiv.style.display == 'none') {
    toggleList.textContent = 'Hide list';
    listDiv.style.display = 'block';
  } else {
    toggleList.textContent = 'Show list';  
    listDiv.style.display = 'none';
  }
});

descriptionButton.addEventListener('click', () => {
  descriptionP.innerHTML = descriptionInput.value + ':';
  descriptionInput.value = '';
});

addItemButton.addEventListener('click', () => {
  let ul = document.getElementsByTagName('ul')[0];                             
  let li = document.createElement('li');
  li.textContent = addItemInput.value;
  ul.appendChild(li);
  addItemInput.value = '';
});
Mel Parker
seal-mask
.a{fill-rule:evenodd;}techdegree
Mel Parker
Front End Web Development Techdegree Student 7,932 Points
Mel Parker
.a{fill-rule:evenodd;}techdegree
Mel Parker
Front End Web Development Techdegree Student 7,932 Points

the index.html file

<!DOCTYPE html>
<html>
  <head>
    <title>JavaScript and the DOM</title>
    <link rel="stylesheet" href="css/style.css">
  </head>
  <body>
    <h1 id="myHeading">JavaScript and the DOM</h1>
    <p>Making a web page interactive</p>
    <button id="toggleList">Hide list</button>
    <div class="list">    
      <p class="description">Things that are purple:</p>
      <input type="text" class="description">
      <button class="description">Change list description</button>
      <ul>
        <li>grapes 
         <button class="up">Up</button>
         <button class="down">Down</button>
         <button class="remove">Remove</button>
        <li>amethyst 
         <button class="up">Up</button>
         <button class="down">Down</button>
         <button class="remove">Remove</button>
        </li>
        <li>lavender 
         <button class="up">Up</button>
         <button class="down">Down</button>
         <button class="remove">Remove</button>
        </li>
        <li>plums 
         <button class="up">Up</button>
         <button class="down">Down</button>
         <button class="remove">Remove</button>
        </li>
      </ul>
      <input type="text" class="addItemInput">
      <button class="addItemButton">Add Item</button>
    </div>
    <script src="app.js"></script>
  </body>
</html>

2 Answers

jb30
jb30
44,807 Points
jb30
jb30
44,807 Points 
if (event.target.className == 'up') {
    let li = event.target.parentNode;
    let prevLi = li.previousElementSibling;
    let ul = li.parentNode;
    if (prevLi) {
      ul.inserBefore(li, prevLi);
   }
  }

It looks like you have a spelling error. You have ul.inserBefore(li, prevLi); rather than ul.insertBefore(li, prevLi);, and a similar issue later when you have ul.inserBefore(nextLi, li); and not ul.insertBefore(nextLi, li);.