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 DOM Scripting By Example Editing and Filtering Names Fix DOM Manipulation Code

Fix DOM Manipulation Code

I have tried several things and nothing is working. Anybody know the answer to this one?

const laws = document.getElementsByTagName('li');
const indexText = document.getElementById('boldIndex');
const button = document.getElementById('embolden');

button.addEventListener('click', (e) => {
    const index = parseInt(indexText.value, 10);

    for (let i = 0; i < laws.length; i += 1) {
       let law = laws[i];

       // replace 'false' with a correct test condition on the line below
       if (index === law) {

           law.style.fontWeight = 'bold';
       } else {
           law.style.fontWeight = 'normal';
<!DOCTYPE html>
  <title>Newton's Laws</title>
  <h1>Newton's Laws of Motion</h1>
    <li>An object in motion tends to stay in motion, unless acted on by an outside force.</li>
    <li>Acceleration is dependent on the forces acting upon an object and the mass of the object.</li>
    <li>For every action, there is an equal and opposite reaction.</li>
  <input type="text" id="boldIndex">
  <button id="embolden">Embolden</button>
  <script src="app.js"></script>
Tri Pham
Tri Pham
18,671 Points

Index is an int (E.g. 1, 2, 3..). law or laws[i] is one item from the document.getElementsByTagName('li') list. They'll never equal.

1 Answer

Umesh Ravji
Umesh Ravji
42,361 Points

Hi Sheryl

What the user enters is an index number: 0, 1, or 2. The for loop iterates over the laws list and each iteration provides you with an variable i that is the index of the current law item. You need to compare the user entered value of index with the value of the i variable (so the element at that index can be changed).

Thank you for the explanation. I get that. I just can't figure out what the code is that does that.

Umesh Ravji
Umesh Ravji
42,361 Points
if (index === i) {
    // code that changes font weight


Thank you. I knew I was overthinking it. I just couldn't figure out how.