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

Posted by Sheryl Darroch
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Sheryl Darroch
Treehouse Project Reviewer

Fix DOM Manipulation Code

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

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 (index === law) {

           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>
Tri Pham
Tri Pham
18,671 Points
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
42,386 Points
Umesh Ravji
Umesh Ravji
42,386 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).

Sheryl Darroch
.a{fill-rule:evenodd;}techdegree seal-36
Sheryl Darroch
Treehouse Project Reviewer

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
42,386 Points
Umesh Ravji
Umesh Ravji
42,386 Points 
if (index === i) {
    // code that changes font weight
}
Sheryl Darroch
.a{fill-rule:evenodd;}techdegree seal-36
Sheryl Darroch
Treehouse Project Reviewer

Umesh,

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