Full height of a html element (div) including border, padding and margin?

What about something like this (no jquery)? It's similar to @gdoron's answer but a little simpler. Tested it in IE9+, Firefox, and Chrome.

function getAbsoluteHeight(el) {
  // Get the DOM Node if you pass in a string
  el = (typeof el === 'string') ? document.querySelector(el) : el; 

  var styles = window.getComputedStyle(el);
  var margin = parseFloat(styles['marginTop']) +
               parseFloat(styles['marginBottom']);

  return Math.ceil(el.offsetHeight + margin);
}

Here is a working jsfiddle.

If you can use jQuery:

$('#divId').outerHeight(true) // gives with margins.

jQuery docs

For vanilla javascript you need to write a lot more (like always...):

function Dimension(elmID) {
    var elmHeight, elmMargin, elm = document.getElementById(elmID);
    if(document.all) {// IE
        elmHeight = elm.currentStyle.height;
        elmMargin = parseInt(elm.currentStyle.marginTop, 10) + parseInt(elm.currentStyle.marginBottom, 10) + "px";
    } else {// Mozilla
        elmHeight = document.defaultView.getComputedStyle(elm, '').getPropertyValue('height');
        elmMargin = parseInt(document.defaultView.getComputedStyle(elm, '').getPropertyValue('margin-top')) + parseInt(document.defaultView.getComputedStyle(elm, '').getPropertyValue('margin-bottom')) + "px";
    }
    return (elmHeight+elmMargin);
}

​ Live DEMO

code source