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

Brian Thomas
Brian Thomas
10,688 Points
Posted by Brian Thomas
Brian Thomas
10,688 Points

Not sure how this code is not adding the class name highlight to the p tags. Can someone help explain?

.

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

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    let ul = e.target.parentNode;
    let p = e.target.previousElementSibling;
    p.addClass('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

John McGarvey
John McGarvey
14,026 Points

Brian, I think the problem is that the addClass() method comes from jQuery. I don't think it exists in vanilla javascript. I think you can do p.className = 'highlight' , and I think that would be accepted as an answer to the quiz, but of course it has the unfortunate side effect that if the paragraph had a class value, it would be replaced, not added to.

I am kind of new to javascript, so this answer is provisional.

Adam Yarber
Adam Yarber
7,373 Points

Brian, I can confirm that replacing p.AddClass('highlight') with p.className = 'highlight'; will be correct for this code challenge!