Get CSS value with JavaScript

Question

How would I get the value of a CSS attribute on an element with vanilla JavaScript? I have tried:

const x = document.getElementById("arrow")
if (x.style.left = "100px") {
console.log(“Hello”)
}

I have also tried replacing “100px” with 100, but it still cannot read the property of null. Here’s my HTML body:

<div id="arrow"></div>

Here’s the CSS:

#arrow {
width: 6px;
height: 100px;
left: 100px;
position: absolute;
}

Thank you!

Answer 1

i don't know why but while sending u answer it is showing
something went wrong

so i have made a code (with explanation )
u can using
1. cssText to get only inline style
2. getComputedStyle

https://code.sololearn.com/W56FK2ekeorM

Answer 2

Maybe you were looking for this one

https://developer.mozilla.org/en-US/docs/Web/API/Window/getComputedStyle