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

matthew glen
matthew glen
14,153 Points
Posted by matthew glen
matthew glen
14,153 Points

Can someone please explain where i'm going wrong here?

I'm taking the users input value and if its equal to li element stored in law the code should run???

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.value === law[i]) {

           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>

2 Answers

Adam N
Adam N
70,280 Points

The index variable holds the number that is put into the input field. Doing.value on a number doesn't make sense. The law variable holds the li element at the current iteration the loop is on (0, 1, or 2). Selecting the i-th element of law with law[i] is like trying to take the i-th element of an li element, which also doesn't make sense.

Let me know if that helps here.

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

Adam makes good points, but it also doesn't make sense to compare a value with an element. All you really need here is to compare the "index" that was entered to the loop variable.

matthew glen
matthew glen
14,153 Points
matthew glen
matthew glen
14,153 Points

Yep got it straight away, thanks very much guys. Much appreciated :)