javascript - Get the height of an element minus padding, margin, border widths

Question

Does anyone know if it's possible to get just the height of an element (minus vertical padding, border, and margin) when there is no inline height declaration? I need to support IE8 and above.

el.style.height doesn't work because the styles are set in an external style sheet.

el.offsetHeight or el.clientHeight doesn't work because they include more than just the element's height. And I can't just subtract the element's padding, etc. because those values are also set in a CSS stylesheet, and not inline (and so el.style.paddingTop doesn't work).

Also can't do window.getComputedStyle(el) because IE8 doesn't support this.

jQuery has the height() method, which offers this, but I'm not using jQuery in this project, plus I just want to know how to do this in pure JavaScript.

Anyone have any thoughts? Much appreciated.

Answer 1

Here's the solution that works for both cases of box-sizing: content-box and border-box.

var computedStyle = getComputedStyle(element);

elementHeight = element.clientHeight;  // height with padding
elementWidth = element.clientWidth;   // width with padding

elementHeight -= parseFloat(computedStyle.paddingTop) + parseFloat(computedStyle.paddingBottom);
elementWidth -= parseFloat(computedStyle.paddingLeft) + parseFloat(computedStyle.paddingRight);

Works in IE9+

You can use feature detection

if (!getComputedStyle) { alert('Not supported'); } 

This will not work if element's display is inline. Use inline-block or use getBoundingClientRect.