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

Tim Frankie
Tim Frankie
7,181 Points
Posted by Tim Frankie
Tim Frankie
7,181 Points

I think there is more to this solution than I am putting. I thought all I should need it list.className = 'hightlight';

I don't really know where to go from here I thought I had it right but it says I am not selecting the proper element

app.js 
const list = document.getElementsByTagName('ul')[0];

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    list.className = 'highlight';
  }
});
index.html 
<!DOCTYPE html>
<html>
    <head>
        <title>JavaScript and the DOM</title>
    </head>
    <link rel="stylesheet" href="style.css" />
    <body>
        <section>
            <h1>Making a Webpage Interactive</h1>
            <p>Things to Learn</p>
            <ul>
                <li><p>Element Selection</p><button>Highlight</button></li>
                <li><p>Events</p><button>Highlight</button></li>
                <li><p>Event Listening</p><button>Highlight</button></li>
                <li><p>DOM Traversal</p><button>Highlight</button></li>
            </ul>
        </section>
        <script src="app.js"></script>
    </body>
</html>

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

A collection (like "list") does not have a "className" property.

Only individual elements have that property. But you wouldn't want to do that to the whole list anyway.

Let's take another look at the instructions: "When any one of the buttons is clicked, a class of highlight should be added to the paragraph element immediately preceding that button ...". So you'll want to use the current button (e.target) as a basis and then navigate to the paragraph element that occurs before it in the DOM. Add the class to that element.