Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

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

brendon hanson
brendon hanson
6,191 Points
Posted by brendon hanson
brendon hanson
6,191 Points

HELP! Only works with one button. Quiz

I can't figure out how to get every button from the DOM

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

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    button.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
231,261 Points
Steven Parker
Steven Parker
231,261 Points

You have the right idea, but instead of referencing a previously selected button, you need to change the sibling of the event target (e.target). You won't need to create a "button" variable.

brendon hanson
brendon hanson
6,191 Points
brendon hanson
brendon hanson
6,191 Points

I don't get what you mean by "Change sibling of e.target" I tried this and thought for sure it would work but it doesn't

const list = document.getElementsByTagName('ul')[0];
list.addEventListener('click', function(e) {
   let li = list.nextElementSibling;
  if (e.target.tagName == 'BUTTON') {
          li.nextElementSibling.className = 'highlights';
  }
});
Steven Parker
Steven Parker
231,261 Points
Steven Parker
Steven Parker
231,261 Points

What I meant was:

    button.previousElementSibling.className = 'highlight';    // instead of this...
    e.target.previousElementSibling.className = 'highlight';  // you could write THIS

You don't need to create any new variables.

brendon hanson
brendon hanson
6,191 Points
brendon hanson
brendon hanson
6,191 Points

I just tried that and it didn't work...

brendon hanson
brendon hanson
6,191 Points
brendon hanson
brendon hanson
6,191 Points

Nvm, lol it works! I said highlights instead of highlight on accident