code: function (element, className) {
  		var elemClassName;
  		while (element) {
  			elemClassName = attr(element, 'class');
  			if (elemClassName) {
  				if (elemClassName.indexOf(className) !== -1) {
  					return true;
  				} else if (elemClassName.indexOf(PREFIX + 'container') !== -1) {
  					return false;
  				}
  			}
  			element = element.parentNode;
  		}		
  	}
docs: Utility to detect whether an element has, or has a parent with, a specific
  class name. Used on detection of tracker objects and on deciding whether
  hovering the tooltip should cause the active series to mouse out.