d3_selectionPrototype.property = function(name, value) {

  // If no value is specified, return the first value.
  if (arguments.length < 2) return this.node()[name];

  function propertyNull() {
    delete this[name];
  }

  function propertyConstant() {
    this[name] = value;
  }

  function propertyFunction() {
    var x = value.apply(this, arguments);
    if (x == null) delete this[name];
    else this[name] = x;
  }

  return this.each(value == null
      ? propertyNull : (typeof value === "function"
      ? propertyFunction : propertyConstant));
};