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

Posted by Zachary Pierpont
Zachary Pierpont
6,236 Points

Bummer: One or more of the buttons do not affect their previous sibling paragraphs. What is wrong with my code?

When I preview this code it seems to be working properly. Every button is highlighting the paragraph before it, am I right? Or am I doing something wrong?

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

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    let button = event.target;
    let par = button.previousElementSibling;
    par.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>

2 Answers

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

There is a stray space in the string " highlight".

And since the event object was passed in as "e", you should use "e.target" instead of "event.target". The latter will work in current browsers, but this behavior should not be depended on.

Zachary Pierpont
Zachary Pierpont
6,236 Points

Thank you, kind sir!

Gergely Bocz
Gergely Bocz
14,244 Points
Gergely Bocz
Gergely Bocz
14,244 Points

Hi Zachary!

There is just a small typo at the 7th line: You have an extra space before highlight. So you wrote " highlight" instead of "highlight". I think the test looks for a literal match and that's why it deemed your answer incorrect.

Zachary Pierpont
Zachary Pierpont
6,236 Points

Thank you!