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

Posted by Marcelo Velasquez
Marcelo Velasquez
Courses Plus Student 6,970 Points

Adding a class name

I can access the sibling element of the button as the exercise request but I can only remove it with the removeChild method, but I don't understand how to add a class name to a child element.

Any help??

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

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
        let li = event.target.parentNode;
        let ul = li.parentNode;
        //ul.removeChild(li);
      }
});
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>

2 Answers

Steven Parker
Steven Parker
229,786 Points
Steven Parker
Steven Parker
229,786 Points

You still need to access the sibling element. The current code access the parent li and it's parent ul, but you don't need either of those. The previousElementSibling property might be useful here.

And when you get to the sibling, you can overwrite it's classes entirely by assigning the className property, or you can just add to whatever might be there using the classList.add() method.

Marcelo Velasquez
PLUS
Marcelo Velasquez
Courses Plus Student 6,970 Points
Marcelo Velasquez
Marcelo Velasquez
Courses Plus Student 6,970 Points

Awesome, thanks for your help.