Use proper window object for iframe in enter/leave

src/eventPlugins/EnterLeaveEventPlugin.js

@@ -81,14 +81,23 @@ var EnterLeaveEventPlugin = {
       return null;
     }
 
+    var win;
+    if (topLevelTarget != null && topLevelTarget.window === topLevelTarget) {
+      // topLevelTarget probably is a window object
+      win = topLevelTarget;
+    } else {
+      var doc = topLevelTarget.ownerDocument;
+      win = doc.defaultView || doc.parentWindow;
+    }
+
     var from, to;
     if (topLevelType === topLevelTypes.topMouseOut) {
       from = topLevelTarget;
       to =
         getFirstReactDOM(nativeEvent.relatedTarget || nativeEvent.toElement) ||
-        window;
+        win;
     } else {
-      from = window;
+      from = win;
       to = topLevelTarget;
     }
 

src/eventPlugins/__tests__/EnterLeaveEventPlugin-test.js

@@ -0,0 +1,64 @@
+/**
+ * Copyright 2013 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * @jsx React.DOM
+ * @emails react-core
+ */
+
+"use strict";
+
+var EnterLeaveEventPlugin;
+var EventConstants;
+var React;
+var ReactMount;
+
+var topLevelTypes;
+
+describe('EnterLeaveEventPlugin', function() {
+  beforeEach(function() {
+    require('mock-modules').dumpCache();
+
+    EnterLeaveEventPlugin = require('EnterLeaveEventPlugin');
+    EventConstants = require('EventConstants');
+    React = require('React');
+    ReactMount = require('ReactMount');
+
+    topLevelTypes = EventConstants.topLevelTypes;
+  });
+
+  it('should set relatedTarget properly in iframe', function() {
+    var iframe = document.createElement('iframe');
+    document.body.appendChild(iframe);
+
+    var component = React.renderComponent(<div />, iframe.contentDocument.body);
+    var div = component.getDOMNode();
+
+    var extracted = EnterLeaveEventPlugin.extractEvents(
+      topLevelTypes.topMouseOver,
+      div,
+      ReactMount.getID(div),
+      {target: div}
+    );
+    expect(extracted.length).toBe(2);
+
+    var leave = extracted[0];
+    var enter = extracted[1];
+
+    expect(leave.target).toBe(iframe.contentWindow);
+    expect(leave.relatedTarget).toBe(div);
+    expect(enter.target).toBe(div);
+    expect(enter.relatedTarget).toBe(iframe.contentWindow);
+  });
+});