Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

JavaScript JavaScript and the DOM (Retiring) Getting a Handle on the DOM Selecting Multiple Elements

Vasco Ramalho
Vasco Ramalho
1,998 Points
Posted by Vasco Ramalho
Vasco Ramalho
1,998 Points

document.querrySelectorAll

selection methods

index.html 
<!DOCTYPE html>
<html>
  <head>
    <title>Rainbow!</title>
  </head>
  <body>
    <ul id="rainbow">
      <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="js/app.js"></script>
  </body>
</html>
js/app.js 
let listItems = document.querySelectorAll("rainbow");
const colors = ["#C2272D", "#F8931F", "#FFFF01", "#009245", "#0193D9", "#0C04ED", "#612F90"];

for(var i = 0; i < colors.length; i ++) {
  listItems[i].style.color = colors[i];    
}

2 Answers

Sean T. Unwin
Sean T. Unwin
28,660 Points
Sean T. Unwin
Sean T. Unwin
28,660 Points

querySelector and querySelectoryAll parameters need to be prefaced with a dot (.) for classes and a hash (#) for an id. If the parameter is not prefaced with one of those characters then the function will assume a tag is given.

Furthernore, you want to be accessing the list items, as opposed to the list as whole, i.e. ('ul').

In this case, we can use querySelectorAll with li as the parameter. Now, in a real scenario we don't necessarily want to grab all the li elements in the page. This takes us back to the first point I made -- use the id selector + rainbow then a space and finally the tags to grab. This is exactly the same way we could select the same elements in CSS.

Don't forget to enclose it with quotes as the function takes a String.

Dan Weru
Dan Weru
47,649 Points
Dan Weru
Dan Weru
47,649 Points 
let listItems = document.querySelectorAll("#rainbow");
const colors = ["#C2272D", "#F8931F", "#FFFF01", "#009245", "#0193D9", "#0C04ED", "#612F90"];

for(var i = 0; i < colors.length; i++) {
  listItems[i].style.color = colors[i];    
}

To select elements with an id, use the # (hash) sign infront of the selector. Also there is no space between i and ++.

Sean T. Unwin
Sean T. Unwin
28,660 Points
Sean T. Unwin
Sean T. Unwin
28,660 Points

Not to detract from your answer, but the space after the i is provided by the challenge and is valid, in that it will be parsed correctly.