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JavaScript

These are just three line of JS code and very simple to read.

<!DOCTYPE html>
<html>
<body>

<div style="background:red;"></div>
<script>
 let num = 200
 const div = document.querySelector('div')
div.style.width = div.style.height = `${num}px`
</script>

</body>
</html>
/*
Can someone  tell me why the div is square, I think it should
 be empty div because I only set the width, not the height.
*/

'div.style.width' is equal to 'div.style.height' which is equal to ${num}px

So div.style.width and div.style.height share the same value.

Hope that helps.

Thank you so much. That was very helpful.

1 Answer

Dane Parchment
MOD
Dane Parchment
Treehouse Moderator 11,076 Points

You are setting both the width and height at the same time though.

When you do:

div.style.width = div.style.height = `${num}px`

What you are actually writing is:

div.style.height = `${num}px`;
div.style.width = div.style.height;

That's how JavaScript interprets that code.