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

What is the right condition for this if statement?

I've tried everything I know and I can't understand what is the right condition for this if statement? Anyone?

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 (false) {

           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>

1 Answer

Steven Parker
Steven Parker
216,148 Points

:point_right: Don't over-think this one, it's quite simple.

All you need to do here is compare the current loop index with the value that the user has placed in the input box. And to make it easy, the challenge has already created a variable named index and assigned it with the numeric value produced by converting the input field.

You just need to test if the loop index is equal to the user's "index".

Steven, I understood the problem and I agree, it is (or at least seems) simple, but I can't seem to make the condition work... As I understand you take the const index and compare it with the loop that's indexing through the list items and if they match it'll set the appropriate font weight.

What's wrong with this condition then? if (index === law) {

Steven Parker
Steven Parker
216,148 Points

law is the current element, not the loop index (and not a number).

The loop index is the variable declared inside the for statement, and is used to select law from laws, which is i.

Ok, I finally got it :) Thank you for your help!