Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript JavaScript and the DOM (Retiring) Traversing the DOM Sibling Traversal

Hello, I am struggling with the portion of adding the class name to the <p> element. I have tried various methods.

I have tried various methods of adding a class and none of them seem to be what the challenge is looking for. I have also tried innerHTML as an option with no luck. Maybe I am not understanding what the challenge is asking for? Any guidance is greatly appreciated!

Thank you!

var list = document.getElementsByTagName('ul')[0];

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    let li = e.target.parentNode;
    let prevLi = li.previousElementSibling;
      prevLi.insertAdjacentHTML('beforebegin', "<p class = 'highlighted'></p>");
      prevLi.className = 'highlight';
      li.nextElementSibling.nextElementSibling.nextElementSibling.insertAdjacentHTML('beforeBegin' , "<p class = 'highlighted'></p>"); 
      li.nextElementSibling.nextElementSibling.nextElementSibling.className= 'highligh';
<!DOCTYPE html>
        <title>JavaScript and the DOM</title>
    <link rel="stylesheet" href="style.css" />
            <h1>Making a Webpage Interactive</h1>
            <p>Things to Learn</p>
                <li><p>Element Selection</p><button>Highlight</button></li>
                <li><p>Event Listening</p><button>Highlight</button></li>
                <li><p>DOM Traversal</p><button>Highlight</button></li>
        <script src="app.js"></script>

Hi Nathan Gallegos ,

In the above code problem you already have target and you just need to get previous sibling of that target & add classname to it.

var list = document.getElementsByTagName('ul')[0];

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    const para = e.target.previousSibling;
    if(para) para.className = "highlight";

Hope it helps,

1 Answer

Thank you for your help Ashish! I really appreciate it!