1 d3_selectionPrototype.property = function(name, value) {

     2 

     3   // If no value is specified, return the first value.

     4   if (arguments.length < 2) return this.node()[name];

     5 

     6   function propertyNull() {

     7     delete this[name];

     8   }

     9 

    10   function propertyConstant() {

    11     this[name] = value;

    12   }

    13 

    14   function propertyFunction() {

    15     var x = value.apply(this, arguments);

    16     if (x == null) delete this[name];

    17     else this[name] = x;

    18   }

    19 

    20   return this.each(value == null

    21       ? propertyNull : (typeof value === "function"

    22       ? propertyFunction : propertyConstant));

    23 };