diff -r efd9c589177a -r c0b4a8b5a012 toolkit/javascript/d3/src/core/selection-on.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/src/core/selection-on.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,34 @@
+// type can be namespaced, e.g., "click.foo"
+// listener can be null for removal
+d3_selectionPrototype.on = function(type, listener, capture) {
+  if (arguments.length < 3) capture = false;
+
+  // parse the type specifier
+  var name = "__on" + type, i = type.indexOf(".");
+  if (i > 0) type = type.substring(0, i);
+
+  // if called with only one argument, return the current listener
+  if (arguments.length < 2) return (i = this.node()[name]) && i._;
+
+  // remove the old event listener, and add the new event listener
+  return this.each(function(d, i) {
+    var node = this;
+
+    if (node[name]) node.removeEventListener(type, node[name], capture);
+    if (listener) node.addEventListener(type, node[name] = l, capture);
+
+    // wrapped event listener that preserves i
+    function l(e) {
+      var o = d3.event; // Events can be reentrant (e.g., focus).
+      d3.event = e;
+      try {
+        listener.call(node, node.__data__, i);
+      } finally {
+        d3.event = o;
+      }
+    }
+
+    // stash the unwrapped listener for retrieval
+    l._ = listener;
+  });
+};