code: function (obj) {
  			var size;
  			var test = doc.createElement('span');
  
  			test.innerHTML = '&nbsp;';
  			test.style.position = 'absolute';
  			test.style.lineHeight = '1em';
  			test.style.fontSize = '1em';
  
  			obj.appendChild(test);
  			size = test.offsetHeight;
  			obj.removeChild(test);
  
  			return size;
  		}
docs: http://stackoverflow.com/questions/1955048/get-computed-font-size-for-dom-element-in-js