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

Posted by Neil Martin Orbase
Neil Martin Orbase
4,137 Points

Assistance on what I should reinforce (vids/tutorials?) to get a better understanding of sibling traversal...

I'm having a hard time getting through this particular challenge. Wasn't sure if I needed to edit the HTML to update the button class:

<button class="highlight">Highlight</button>

(If the html file is just a guide not to be touched, then I may really need help on what to understand..):

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

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    document.createElement('.highlight').previousElementSibling;
  }
});
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

Daniel Jong
Daniel Jong
11,071 Points
Daniel Jong
Daniel Jong
11,071 Points

Hi there, you do not need to edit your html in order complete this challenge. In order to add a class you need className instead of createElement which is used to create an element. You need to get the previous element sibling of the target element which is button in this case and set the className to "highlight".

Here's how I solve it:

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

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    e.target.previousElementSibling.className = "highlight";
  }
});

Hope this helps!