curriculum/challenges/english/blocks/learn-responsive-web-design-by-building-a-piano/612e813b3ba67633222cbe54.md
Remember that a class attribute can have multiple values. To separate your white keys from your black keys, you'll add a second class value of black--key. Add this to your second, third, fifth, sixth, and seventh .key elements.
Your second .key element should also have a class of black--key.
const key = document.querySelectorAll('.key')?.[1];
assert(key?.className?.includes('black--key'));
Your third .key should have black--key in the class.
const third = document.querySelectorAll('.key')?.[2];
assert(third?.classList?.contains('black--key'));
Your fifth .key should have black--key in the class.
const fifth = document.querySelectorAll('.key')?.[4];
assert(fifth?.classList?.contains('black--key'));
Your sixth .key should have black--key in the class.
const sixth = document.querySelectorAll('.key')?.[5];
assert(sixth?.classList?.contains('black--key'));
Your seventh .key should have black--key in the class.
const seventh = document.querySelectorAll('.key')?.[6];
assert(seventh?.classList?.contains('black--key'));
You should have five .black--key elements.
const blackKeys = document.querySelectorAll('.black--key');
assert(blackKeys?.length === 5);
You should have seven .key elements.
const keys = document.querySelectorAll('.key');
assert(keys?.length === 7);
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<title>Piano</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
</head>
<body>
--fcc-editable-region--
<div id="piano">
<div class="keys">
<div class="key"></div>
<div class="key"></div>
<div class="key"></div>
<div class="key"></div>
<div class="key"></div>
<div class="key"></div>
<div class="key"></div>
</div>
</div>
--fcc-editable-region--
</body>
</html>