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

Gawel Konefeld
Gawel Konefeld
2,307 Points
Posted by Gawel Konefeld
Gawel Konefeld
2,307 Points

I can`t find mistake...

I know that in this challange task i have target <p> element which is next to <button> element and i don`t know why command previousElementSibling does not work in this case. Thanks for help! :)

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

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
      e.target.previousElementSibling.className.add == '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

Neil McPartlin
Neil McPartlin
14,662 Points
Neil McPartlin
Neil McPartlin
14,662 Points

Hi Gawel, Just 2 issues I see.

  1. When using == or ===, you are making a comparison between values found on either side. But in this challenge, you want to 'set' the parameter on the left, to be the value provided on the right, so just use a single ' = '.

  2. You won't need the .add either. You will simply be setting 'className' to be ''highlight'.

So this will work...

e.target.previousElementSibling.className = 'highlight';

Gawel Konefeld
Gawel Konefeld
2,307 Points
Gawel Konefeld
Gawel Konefeld
2,307 Points

Thanks very much Neil !!! :)