code: function getOverflowStyles(e) {
      // When the <html> element has an overflow style of 'visible', it assumes
      // the overflow style of the body, and the body is really overflow:visible.
      var overflowElem = e;
      if (htmlOverflowStyle == 'visible') {
        // Note: bodyElem will be null/undefined in SVG documents.
        if (e == htmlElem && bodyElem) {
          overflowElem = bodyElem;
        } else if (e == bodyElem) {
          return {x: 'visible', y: 'visible'};
        }
      }
      var overflow = {
        x: bot.dom.getEffectiveStyle(overflowElem, 'overflow-x'),
        y: bot.dom.getEffectiveStyle(overflowElem, 'overflow-y')
      };
      // The <html> element cannot have a genuine 'visible' overflow style,
      // because the viewport can't expand; 'visible' is really 'auto'.
      if (e == htmlElem) {
        overflow.x = overflow.x == 'visible' ? 'auto' : overflow.x;
        overflow.y = overflow.y == 'visible' ? 'auto' : overflow.y;
      }
      return overflow;
    }
docs: Return the x and y overflow styles for the given element.