code: function(start, handler, arg) {
  		this.global = true;
  		this.descend(start, handler, arg);
  		this.global = false;
  	}
docs: Crawl DOM descending, transcend into iframes.
  @param {object} start Spirit or Element
  @param {object} handler
  @param @optional {object} arg @TODO: is this even supported?