
For left-to-right OS they are always the widths of left/top borders.


If your browser reserves the space for a scrollbar (most browsers for Windows do), then you can test it below. Such cross-browser differences is the reason not to use getComputedStyle, but rather rely on geometry properties. Firefox) – CSS width (ignore the scrollbar). Chrome) return the real inner width, minus the scrollbar, and some of them (e.g. …But with getComputedStyle(elem).width the situation is different. And clientWidth/clientHeight take that into account.

So the real width available for the content is less than CSS width. Sometimes the code that works fine without a scrollbar becomes buggy with it, because a scrollbar takes the space from the content in some browsers. So here CSS width is useless.Īnd there’s one more reason: a scrollbar. Alert( getComputedStyle(elem).width ) // autoįrom the CSS standpoint, width:auto is perfectly normal, but in JavaScript we need an exact size in px that we can use in calculations.
