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

McKay Thayn
PLUS
McKay Thayn
Courses Plus Student 6,064 Points

Complete the code to add a class of highlight to a <p> element that's an immediate previous sibling of the button

I stopped programming for a few days so I rewatched the video associated with the task but I'm still a little lost as to how to highlight the <p> through Javascript. Do I need to just parentNode all the way up to P?

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

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    let li = event.target.parentNode;
    let ul = li.previousElementSibling;
    ul.class = '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
229,982 Points

Some hints:

  • the paragraph is the sibling of the button itself
  • you won't need to reference the parent element for this challenge
McKay Thayn
McKay Thayn
Courses Plus Student 6,064 Points
var list = document.getElementsByTagName('ul')[0];

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    let p = e.target.siblingNode;
    p.class = 'highlight';
  }
});

Am I getting closer?

Steven Parker
Steven Parker
229,982 Points

You're getting closer, but:

  • "siblingNode" is not an element property, did you mean "previousElementSibling"?
  • the name of the property that holds class information is not "class" but "className"
McKay Thayn
PLUS
McKay Thayn
Courses Plus Student 6,064 Points

That worked! yep forgot to add Name to class (className) Don't know what I was thinking with the siblingNode thing

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

This worked