(function() {
  
  function get(node, name){
    while (!(name in node)) if (!(node = node.parentNode)) return;
    return node[name];
  }

  d3.selection.prototype.local = function(name, value) {
    return arguments.length > 1
        ? this.property(name, value)
        : get(this.node(), name);
  }
	
})();