What is the scrollbar width?

Write the code that returns the width of a standard scrollbar.

For Windows it usually varies between 12px and 20px. If the browser doesn’t reserves any space for it, then it may be 0px.

P.S. The code should work for any HTML document, do not depend on its content.

To get the scrollbar width, we can create an element with the scroll, but without borders and paddings.

Then the difference between its full width offsetWidth and the inner content area width clientWidth will be exactly the scrollbar:

// create a div with the scroll
let div = document.createElement('div');

div.style.overflowY = 'scroll';
div.style.width = '50px';
div.style.height = '50px';

// must put it in the document, otherwise sizes will be 0
document.body.append(div);
let scrollWidth = div.offsetWidth - div.clientWidth;

div.remove();

alert(scrollWidth);