1 function d3_selection(groups) {

     2   d3_arraySubclass(groups, d3_selectionPrototype);

     3   return groups;

     4 }

     5 

     6 var d3_select = function(s, n) { return n.querySelector(s); },

     7     d3_selectAll = function(s, n) { return n.querySelectorAll(s); };

     8 

     9 // Prefer Sizzle, if available.

    10 if (typeof Sizzle === "function") {

    11   d3_select = function(s, n) { return Sizzle(s, n)[0]; };

    12   d3_selectAll = function(s, n) { return Sizzle.uniqueSort(Sizzle(s, n)); };

    13 }

    14 

    15 var d3_selectionPrototype = [];

    16 

    17 d3.selection = function() {

    18   return d3_selectionRoot;

    19 };

    20 

    21 d3.selection.prototype = d3_selectionPrototype;