docs: function isHidden(element) {
  
  	var parent_styles,
  	    overflow_x,
  	    overflow_y,
  	    overflow,
  	    parent = element.parentNode,
  	    styles;
  
  	if (!parent) {
  		return true;
  	}
  
  	// Always return false for the document element
  	if (isDocumentElement(parent)) {
  		return false;
  	}
  
  	// Get the computed styles of the element
  	styles = getStyle(element);
  
  	// Return true if the element is invisible
  	if (   styles.opacity === '0'
  		|| styles.display === 'none'
  		|| styles.visibility === 'hidden') {
  		return true;
  	}
  
  	return isHidden(parent);
  }