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JavaScript JavaScript and the DOM (Retiring) Traversing the DOM Child Traversal

Posted by Hanwen Zhang
Hanwen Zhang
20,084 Points

Why my code is wrong? I thought the paragraph is the child to the section.

Next, change the color of each child paragraph to blue.

(Remember: paragraphs is a collection of elements, so you'll first need to use a loop to access each element in the collection.)

app.js 
var section = document.querySelector('section');
var paragraphs = section.children;

for ( let i=0; i<section.length, i++ ) {
  section [i] .style.color= "blue';
}
index.html 
<!DOCTYPE html>
<html>
    <head>
        <title>Child Traversal</title>
    </head>
    <body>
        <section>
            <p>This is the first paragraph</p>
            <p>This is a slightly longer, second paragraph</p>
            <p>Shorter, last paragraph</p>
        </section>
        <footer>
            <p>&copy; 2019</p> 
        </footer>
        <script src="app.js"></script>
    </body>
</html>

1 Answer

Peter Vann
Peter Vann
36,425 Points

Hi Hanwen!

Your first two lines are exactly correct.

To pass both challenges using a regular for loop you'd want this:

var section = document.querySelector('section');
var paragraphs = section.children;

for (let i=0; i < paragraphs.length; i++ ) { // Make sure to use semicolons and not commas here
  paragraphs[i].style.color= 'blue'; // Use paragraphs, not section, since that's the collection you're intending to modify
}

Although I opted to use a for/of loop (which also passed) like this:

var section = document.querySelector('section');
var paragraphs = section.children;

for (let p of paragraphs) {
    p.style.color = 'blue';
}

But either way passes and therefore both are reasonable ways to achieve the right result.

I hope that helps.

Stay safe and happy coding!

Hanwen Zhang
Hanwen Zhang
20,084 Points

Thank you Peter