code: function computeStyle(f) {
  
      // get style properties
      var style = w.getComputedStyle(f.element, null);
  
      // get current font size in pixels (if we already calculated it, use the calculated version)
      f.currentFontSize = parseInt(style.getPropertyValue('font-size'), 10);
  
      // get display type and wrap mode
      f.display = style.getPropertyValue('display');
      f.whiteSpace = style.getPropertyValue('white-space');
    }
docs: every fitty element is tested for invalid styles