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

Kevin Horwitz
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.a{fill-rule:evenodd;}techdegree
Kevin Horwitz
Full Stack JavaScript Techdegree Student 3,076 Points
Posted by Kevin Horwitz
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Kevin Horwitz
Full Stack JavaScript Techdegree Student 3,076 Points

I'm having some trouble figuring this one out. Any help is much appreciated!

I can't seem to figure out how to select a specific li element within the code given. I always seems to grab all or none

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.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

Robert Gulley
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Robert Gulley
Front End Web Development Techdegree Student 10,722 Points

Hi Kevin! -

You're wanting to find out if the number in the "indexText" is equal to the index of your for loop. In order to do this, we get the value from the input field in the constant indexText. We then parse this to an integer and the constant index just below the button listener. Now we simply need to compare that to the index of the for loop, so the code would look like the following:

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 === i) {

           law.style.fontWeight = 'bold';
       } else {
           law.style.fontWeight = 'normal';
       }
    }
});

Hope this helps!