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

Front End Web Development Techdegree Graduate 18,873 Points

Three list item

I actually tried many method to the condition, but i still cant figure out, which one to use it? So , i tried index == law.indexOf(), or index == law and so on.

But all doesnt work, so hope someone help me out, thank you so much!!

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) {

  = 'bold';
       } else {
  = '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>

2 Answers

You need to check if the current loop iteration which is represented by ā€œiā€ is equal to the index stored in the index variable. the loop runs through the array of the list items, if u want to bold the second list item, u enter 1 on the input >>> the loop starts to run, first the i is equal to 0, and u entered 1 so the list item is still normal, in the second iteration ā€œiā€ is equal to 1 and u entered 1 so the second list item get bolded.

Front End Web Development Techdegree Graduate 18,873 Points

I know the array list index. But i just dont know why the result is index == i, but not index == law.indexOf()?

because the variable "law" is holding the array of the list items(li) why would u want to compare them?\ instead the variable "index" is holding the user's input value and u compare it with the "i" variable beacause "i" reprsenting the current iteration the loop is on.