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

Steven Carbuhn
Steven Carbuhn
13,020 Points
Posted by Steven Carbuhn
Steven Carbuhn
13,020 Points

Sibling Traversal Test

I've already found the solution for this, but i'm curious as to why this does not satisfy the requirement? Why does ".addClassName()" not work? as opposed to "className ="

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

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    e.target.previousElementSibling.addClassName('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>
Mario Sanchez Carrion
Mario Sanchez Carrion
17,541 Points
Mario Sanchez Carrion
Mario Sanchez Carrion
17,541 Points

I haven't found any reference to addClassName() as being a valid JS function. Try this: e.target.previousElementSibling.classList.add('highlight')