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

Posted by usmantahir
usmantahir
6,584 Points

Need help to solve this condition

There are three list items in the index.html file. We want to be able to enter a 0, 1 or 2 in the text field to embolden the list item with the corresponding index. Can you figure out what condition to put into the if statement to make this code work?

app.js 
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';
       }
    }
});
index.html 
<!DOCTYPE html>
<html>
<head>
  <title>Newton's Laws</title>
</head>
<body>
  <h1>Newton's Laws of Motion</h1>
  <ul>
    <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>
  </ul>
  <input type="text" id="boldIndex">
  <button id="embolden">Embolden</button>
  <script src="app.js"></script>
</body>
</html>

3 Answers

Brodey Newman
Brodey Newman
10,962 Points
Brodey Newman
Brodey Newman
10,962 Points

Hey terrycheney,

The below code should help.

if (index === i)

If you would like an explanation, let me know!

usmantahir
usmantahir
6,584 Points

thanks for help

Felix Yakubov
Felix Yakubov
17,475 Points
Felix Yakubov
Felix Yakubov
17,475 Points

I would like an explanation :) why does the initial code changes all three li?

Killeon Patterson
Killeon Patterson
18,214 Points
Killeon Patterson
Killeon Patterson
18,214 Points

Could you explain your answer, please?

Sean Flanagan
Sean Flanagan
33,235 Points
Sean Flanagan
Sean Flanagan
33,235 Points

Try

if (i === index)

That works for me.

The trick is not to over-complicate it. You only have to change the condition, not the code block. i has to equal 0, 1 or 2, and indices start with 0. The job is to set i, not to set index.

I hope this explanation helps.