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

Posted by Barry Ort
Barry Ort
12,373 Points

what's the right answer?

what is the correct solution?

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

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    list.previousElementSibling.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
231,271 Points
Steven Parker
Steven Parker
231,271 Points

The className of an element is not a method you can call.

But it is a property you can assign a value to. ("...className = value").

Barry Ort
Barry Ort
12,373 Points

as far as i know it is a method you can call. see: https://teamtreehouse.com/library/changing-element-attributes

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

At about 0:54 in that video, there is an example of it being used as a property. When "input.className" is entered into the console, without parentheses, the current value is returned. Is there another place in the video where you believe you saw it being used as a method instead?

Barry Ort
Barry Ort
12,373 Points

I ended up doing this and it worked. let p = e.target.previousElementSibling p.className = "highlight";

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

You probably didn't actually put that "p" between previousElementSibling and className, but otherwise, that's exactly what I was suggesting. Good job. :+1:

Barry Ort
Barry Ort
12,373 Points

thanx for the help