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 Getting a Handle on the DOM Select by Tag Name

Ali Billow
Ali Billow
2,819 Points
Posted by Ali Billow
Ali Billow
2,819 Points

Working with the DOM - Help with challenge!

The for loop in app.js cycles over list items and applies a color to each item using the values stored in the colors array. For example, it applies the first color in the array ( #C2272D) to the first list item, the second color (#F8931F) to the second list item, and so on.

Complete the code by setting the variable listItems to refer to an HTMLCollection. The collection should contain all list items in the <ul> element.

app.js 
// Complete the challenge by writing JavaScript below
const colors = ["#C2272D", "#F8931F", "#FFFF01", "#009245", "#0193D9", "#0C04ED", "#612F90"];
let listItems;

for ( let i = 0; i < colors.length; i++ ) {
  listItems[i].style.color = colors[i];    
}
index.html 
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <title>JavaScript and the DOM</title>
  </head>
  <body>
    <h1>My List</h1>
    <ul>
      <li>This should be red</li>
      <li>This should be orange</li>
      <li>This should be yellow</li>
      <li>This should be green</li>
      <li>This should be blue</li>
      <li>This should be indigo</li>
      <li>This should be violet</li>
    </ul>
    <script src="app.js"></script>
  </body>
</html>

3 Answers

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

Change the simple declaration of listItems on line 3 to one that also assigns it with the requested HTMLCollection. There are several ways of doing this, but a popular choice is to use the querySelectorAll method.

Sean Poore
Sean Poore
5,365 Points
Sean Poore
Sean Poore
5,365 Points

In app.js you didn't define listItems, you can simply change it to let listItems = document.querySelctor([selector]);

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

The querySelector (also check the spelling) method only selects one element, but this challenge requires a collection. That's why I suggested using querySelectorAll.

Sean Poore
Sean Poore
5,365 Points
Sean Poore
Sean Poore
5,365 Points

If you were to use querySelector on a class and each item in the collection has said class, doesn't that function the same as querySelectorAll?

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

When more than one item matches your selector, querySelector gives you just the first element that matches, but querySelectorAll gives you a collection containing all of them.