diff --git a/.gitignore b/.gitignore
index 88230e825..72ab8b789 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 node_modules
 npm-debug.log
+static/context.js
 static/karma.js
 .idea/*
 *.iml
diff --git a/client/karma.js b/client/karma.js
index 01d5f1e29..d54fe34e2 100644
--- a/client/karma.js
+++ b/client/karma.js
@@ -1,9 +1,8 @@
-var stringify = require('./stringify')
+var stringify = require('../common/stringify')
 var constant = require('./constants')
-var util = require('./util')
+var util = require('../common/util')
 
 var Karma = function (socket, iframe, opener, navigator, location) {
-  var hasError = false
   var startEmitted = false
   var reloadingContext = false
   var self = this
@@ -22,73 +21,47 @@ var Karma = function (socket, iframe, opener, navigator, location) {
   // registry anymore.
   this.socket = socket
 
+  // Set up postMessage bindings for current window
+  // DEV: These are to allow windows in separate processes execute local tasks
+  //   Electron is one of these environments
+  if (window.addEventListener) {
+    window.addEventListener('message', function handleMessage (evt) {
+      // Resolve the origin of our message
+      var origin = evt.origin || evt.originalEvent.origin
+
+      // If the message isn't from our host, then reject it
+      if (origin !== window.location.origin) {
+        return
+      }
+
+      // Take action based on the message type
+      var method = evt.data.method
+      if (!self[method]) {
+        self.error('Received `postMessage` for "' + method + '" but the method doesn\'t exist')
+        return
+      }
+      self[method].apply(self, evt.data.arguments)
+    }, false)
+  }
+
   var childWindow = null
   var navigateContextTo = function (url) {
     if (self.config.useIframe === false) {
-      if (childWindow === null || childWindow.closed === true) {
-        // If this is the first time we are opening the window, or the window is closed
-        childWindow = opener('about:blank')
+      // If there is a window already open, then close it
+      // DEV: In some environments (e.g. Electron), we don't have setter access for location
+      if (childWindow !== null && childWindow.closed !== true) {
+        childWindow.close()
       }
-      childWindow.location = url
+      childWindow = opener(url)
     } else {
       iframe.src = url
     }
   }
 
-  this.setupContext = function (contextWindow) {
-    if (self.config.clearContext && hasError) {
-      return
-    }
-
-    var getConsole = function (currentWindow) {
-      return currentWindow.console || {
-        log: function () {},
-        info: function () {},
-        warn: function () {},
-        error: function () {},
-        debug: function () {}
-      }
-    }
-
-    contextWindow.__karma__ = this
-
-    // This causes memory leak in Chrome (17.0.963.66)
-    contextWindow.onerror = function () {
-      return contextWindow.__karma__.error.apply(contextWindow.__karma__, arguments)
-    }
-
-    contextWindow.onbeforeunload = function (e, b) {
-      if (!reloadingContext) {
-        // TODO(vojta): show what test (with explanation about jasmine.UPDATE_INTERVAL)
-        contextWindow.__karma__.error('Some of your tests did a full page reload!')
-      }
-    }
-
-    if (self.config.captureConsole) {
-      // patch the console
-      var localConsole = contextWindow.console = getConsole(contextWindow)
-      var logMethods = ['log', 'info', 'warn', 'error', 'debug']
-      var patchConsoleMethod = function (method) {
-        var orig = localConsole[method]
-        if (!orig) {
-          return
-        }
-        localConsole[method] = function () {
-          self.log(method, arguments)
-          return Function.prototype.apply.call(orig, localConsole, arguments)
-        }
-      }
-      for (var i = 0; i < logMethods.length; i++) {
-        patchConsoleMethod(logMethods[i])
-      }
-    }
-
-    contextWindow.dump = function () {
-      self.log('dump', arguments)
-    }
-
-    contextWindow.alert = function (msg) {
-      self.log('alert', [msg])
+  this.onbeforeunload = function () {
+    if (!reloadingContext) {
+      // TODO(vojta): show what test (with explanation about jasmine.UPDATE_INTERVAL)
+      self.error('Some of your tests did a full page reload!')
     }
   }
 
@@ -113,7 +86,6 @@ var Karma = function (socket, iframe, opener, navigator, location) {
   // error during js file loading (most likely syntax error)
   // we are not going to execute at all
   this.error = function (msg, url, line) {
-    hasError = true
     var message = msg
 
     if (url) {
@@ -174,28 +146,8 @@ var Karma = function (socket, iframe, opener, navigator, location) {
     }
   }
 
-  var UNIMPLEMENTED_START = function () {
-    this.error('You need to include some adapter that implements __karma__.start method!')
-  }
-
-  // all files loaded, let's start the execution
-  this.loaded = function () {
-    // has error -> cancel
-    if (!hasError) {
-      this.start(this.config)
-    }
-
-    // remove reference to child iframe
-    this.start = UNIMPLEMENTED_START
-  }
-
-  // supposed to be overriden by the context
-  // TODO(vojta): support multiple callbacks (queue)
-  this.start = UNIMPLEMENTED_START
-
   socket.on('execute', function (cfg) {
-    // reset hasError and reload the iframe
-    hasError = false
+    // reset startEmitted and reload the iframe
     startEmitted = false
     self.config = cfg
     // if not clearing context, reloadingContext always true to prevent beforeUnload error
diff --git a/client/main.js b/client/main.js
index 93406c4be..ed9200013 100644
--- a/client/main.js
+++ b/client/main.js
@@ -4,7 +4,7 @@
 require('core-js/es5')
 var Karma = require('./karma')
 var StatusUpdater = require('./updater')
-var util = require('./util')
+var util = require('../common/util')
 
 var KARMA_URL_ROOT = require('./constants').KARMA_URL_ROOT
 
diff --git a/client/stringify.js b/common/stringify.js
similarity index 100%
rename from client/stringify.js
rename to common/stringify.js
diff --git a/client/util.js b/common/util.js
similarity index 100%
rename from client/util.js
rename to common/util.js
diff --git a/context/karma.js b/context/karma.js
new file mode 100644
index 000000000..ba646ec09
--- /dev/null
+++ b/context/karma.js
@@ -0,0 +1,138 @@
+// Load our dependencies
+var stringify = require('../common/stringify')
+
+// Define our context Karma constructor
+var ContextKarma = function (callParentKarmaMethod) {
+  // Define local variables
+  var hasError = false
+  var self = this
+
+  // Define our loggers
+  // DEV: These are intentionally repeated in client and context
+  this.log = function (type, args) {
+    var values = []
+
+    for (var i = 0; i < args.length; i++) {
+      values.push(this.stringify(args[i], 3))
+    }
+
+    this.info({log: values.join(', '), type: type})
+  }
+
+  this.stringify = stringify
+
+  // Define our proxy error handler
+  // DEV: We require one in our context to track `hasError`
+  this.error = function () {
+    hasError = true
+    callParentKarmaMethod('error', [].slice.call(arguments))
+    return false
+  }
+
+  // Define our start handler
+  var UNIMPLEMENTED_START = function () {
+    this.error('You need to include some adapter that implements __karma__.start method!')
+  }
+  // all files loaded, let's start the execution
+  this.loaded = function () {
+    // has error -> cancel
+    if (!hasError) {
+      this.start(this.config)
+    }
+
+    // remove reference to child iframe
+    this.start = UNIMPLEMENTED_START
+  }
+  // supposed to be overriden by the context
+  // TODO(vojta): support multiple callbacks (queue)
+  this.start = UNIMPLEMENTED_START
+
+  // Define proxy methods
+  // DEV: This is a closured `for` loop (same as a `forEach`) for IE support
+  var proxyMethods = ['complete', 'info', 'result']
+  for (var i = 0; i < proxyMethods.length; i++) {
+    (function bindProxyMethod (methodName) {
+      self[methodName] = function boundProxyMethod () {
+        callParentKarmaMethod(methodName, [].slice.call(arguments))
+      }
+    }(proxyMethods[i]))
+  }
+
+  // Define bindings for context window
+  this.setupContext = function (contextWindow) {
+    // If we clear the context after every run and we already had an error
+    //   then stop now. Otherwise, carry on.
+    if (self.config.clearContext && hasError) {
+      return
+    }
+
+    // Perform window level bindings
+    // DEV: We return `self.error` since we want to `return false` to ignore errors
+    contextWindow.onerror = function () {
+      return self.error.apply(self, arguments)
+    }
+    // DEV: We must defined a function since we don't want to pass the event object
+    contextWindow.onbeforeunload = function (e, b) {
+      callParentKarmaMethod('onbeforeunload', [])
+    }
+
+    contextWindow.dump = function () {
+      self.log('dump', arguments)
+    }
+
+    contextWindow.alert = function (msg) {
+      self.log('alert', [msg])
+    }
+
+    // If we want to overload our console, then do it
+    var getConsole = function (currentWindow) {
+      return currentWindow.console || {
+        log: function () {},
+        info: function () {},
+        warn: function () {},
+        error: function () {},
+        debug: function () {}
+      }
+    }
+    if (self.config.captureConsole) {
+      // patch the console
+      var localConsole = contextWindow.console = getConsole(contextWindow)
+      var logMethods = ['log', 'info', 'warn', 'error', 'debug']
+      var patchConsoleMethod = function (method) {
+        var orig = localConsole[method]
+        if (!orig) {
+          return
+        }
+        localConsole[method] = function () {
+          self.log(method, arguments)
+          return Function.prototype.apply.call(orig, localConsole, arguments)
+        }
+      }
+      for (var i = 0; i < logMethods.length; i++) {
+        patchConsoleMethod(logMethods[i])
+      }
+    }
+  }
+}
+
+// Define call/proxy methods
+ContextKarma.getDirectCallParentKarmaMethod = function (parentWindow) {
+  return function directCallParentKarmaMethod (method, args) {
+    // If the method doesn't exist, then error out
+    if (!parentWindow.karma[method]) {
+      parentWindow.karma.error('Expected Karma method "' + method + '" to exist but it doesn\'t')
+      return
+    }
+
+    // Otherwise, run our method
+    parentWindow.karma[method].apply(parentWindow.karma, args)
+  }
+}
+ContextKarma.getPostMessageCallParentKarmaMethod = function (parentWindow) {
+  return function postMessageCallParentKarmaMethod (method, args) {
+    parentWindow.postMessage({method: method, arguments: args}, window.location.origin)
+  }
+}
+
+// Export our module
+module.exports = ContextKarma
diff --git a/context/main.js b/context/main.js
new file mode 100644
index 000000000..89b450c31
--- /dev/null
+++ b/context/main.js
@@ -0,0 +1,21 @@
+// Load in our dependencies
+var ContextKarma = require('./karma')
+
+// Resolve our parent window
+var parentWindow = window.opener || window.parent
+
+// Define a remote call method for Karma
+var callParentKarmaMethod = ContextKarma.getDirectCallParentKarmaMethod(parentWindow)
+
+// If we don't have access to the window, then use `postMessage`
+// DEV: In Electron, we don't have access to the parent window due to it being in a separate process
+// DEV: We avoid using this in Internet Explorer as they only support strings
+//   http://caniuse.com/#search=postmessage
+var haveParentAccess = false
+try { haveParentAccess = !!parentWindow.window } catch (err) { /* Ignore errors (likely permisison errors) */ }
+if (!haveParentAccess) {
+  callParentKarmaMethod = ContextKarma.getPostMessageCallParentKarmaMethod(parentWindow)
+}
+
+// Define a window-scoped Karma
+window.__karma__ = new ContextKarma(callParentKarmaMethod)
diff --git a/gruntfile.js b/gruntfile.js
index 6d644cf4d..42a4423dc 100644
--- a/gruntfile.js
+++ b/gruntfile.js
@@ -5,13 +5,16 @@ module.exports = function (grunt) {
     files: {
       server: ['lib/**/*.js'],
       client: ['client/**/*.js'],
+      common: ['common/**/*.js'],
+      context: ['context/**/*.js'],
       grunt: ['grunt.js', 'tasks/*.js'],
       scripts: ['scripts/init-dev-env.js']
     },
     browserify: {
       client: {
         files: {
-          'static/karma.js': ['client/main.js']
+          'static/karma.js': ['client/main.js'],
+          'static/context.js': ['context/main.js']
         }
       }
     },
@@ -76,7 +79,8 @@ module.exports = function (grunt) {
         '<%= files.grunt %>',
         '<%= files.scripts %>',
         '<%= files.client %>',
-        'static/context.js',
+        '<%= files.common %>',
+        '<%= files.context %>',
         'static/debug.js',
         'test/**/*.js',
         'gruntfile.js'
diff --git a/static/context.js b/static/context.js
deleted file mode 100644
index 49f48f4db..000000000
--- a/static/context.js
+++ /dev/null
@@ -1,13 +0,0 @@
-// Define a placeholder for Karma to be defined via the parent window
-// DEV: This is a placeholder change for upcoming edits in https://github.com/karma-runner/karma/pull/1984
-window.__karma__ = {
-  setupContext: function (contextWindow) {
-    // sets window.__karma__ and overrides console and error handling
-    // Use window.opener if this was opened by someone else - in a new window
-    if (contextWindow.opener) {
-      contextWindow.opener.karma.setupContext(contextWindow)
-    } else {
-      contextWindow.parent.karma.setupContext(contextWindow)
-    }
-  }
-}
diff --git a/test/client/karma.spec.js b/test/client/karma.spec.js
index 462f75d0c..79c390150 100644
--- a/test/client/karma.spec.js
+++ b/test/client/karma.spec.js
@@ -4,11 +4,12 @@ global.JSON = require('json3')
 var sinon = require('sinon')
 var assert = require('assert')
 
-var Karma = require('../../client/karma')
+var ClientKarma = require('../../client/karma')
+var ContextKarma = require('../../context/karma')
 var MockSocket = require('./mocks').Socket
 
 describe('Karma', function () {
-  var socket, k, windowNavigator, windowLocation, windowStub, startSpy, iframe
+  var socket, k, ck, windowNavigator, windowLocation, windowStub, startSpy, iframe, clientWindow
 
   var setTransportTo = function (transportName) {
     socket._setTransportNameTo(transportName)
@@ -22,33 +23,38 @@ describe('Karma', function () {
     windowLocation = {search: ''}
     windowStub = sinon.stub().returns({})
 
-    k = new Karma(socket, iframe, windowStub, windowNavigator, windowLocation)
-    startSpy = sinon.spy(k, 'start')
+    k = new ClientKarma(socket, iframe, windowStub, windowNavigator, windowLocation)
+    clientWindow = {
+      karma: k
+    }
+    ck = new ContextKarma(ContextKarma.getDirectCallParentKarmaMethod(clientWindow))
+    ck.config = {}
+    startSpy = sinon.spy(ck, 'start')
   })
 
   it('should start execution when all files loaded and pass config', function () {
-    var config = {
+    var config = ck.config = {
       useIframe: true
     }
 
     socket.emit('execute', config)
     assert(!startSpy.called)
 
-    k.loaded()
+    ck.loaded()
     assert(startSpy.calledWith(config))
   })
 
   it('should open a new window when useIFrame is false', function () {
-    var config = {
+    var config = ck.config = {
       useIframe: false
     }
 
     socket.emit('execute', config)
-    assert(!k.start.called)
+    assert(!ck.start.called)
 
-    k.loaded()
+    ck.loaded()
     assert(startSpy.calledWith(config))
-    assert(windowStub.calledWith('about:blank'))
+    assert(windowStub.calledWith('context.html'))
   })
 
   it('should stop execution', function () {
@@ -58,27 +64,27 @@ describe('Karma', function () {
   })
 
   it('should not start execution if any error during loading files', function () {
-    k.error('syntax error', '/some/file.js', 11)
-    k.loaded()
-    sinon.spy(k, 'start')
+    ck.error('syntax error', '/some/file.js', 11)
+    ck.loaded()
+    sinon.spy(ck, 'start')
     assert(!startSpy.called)
   })
 
   it('should remove reference to start even after syntax error', function () {
     var ADAPTER_START_FN = function () {}
 
-    k.start = ADAPTER_START_FN
-    k.error('syntax error', '/some/file.js', 11)
-    k.loaded()
-    assert.notEqual(k.start, ADAPTER_START_FN)
+    ck.start = ADAPTER_START_FN
+    ck.error('syntax error', '/some/file.js', 11)
+    ck.loaded()
+    assert.notEqual(ck.start, ADAPTER_START_FN)
 
-    k.start = ADAPTER_START_FN
-    k.loaded()
+    ck.start = ADAPTER_START_FN
+    ck.loaded()
     assert.notEqual(k.start, ADAPTER_START_FN)
   })
 
   it('should not set up context if there was an error', function () {
-    var config = {
+    var config = ck.config = {
       clearContext: true
     }
 
@@ -86,16 +92,15 @@ describe('Karma', function () {
 
     var mockWindow = {}
 
-    k.error('page reload')
-    k.setupContext(mockWindow)
+    ck.error('page reload')
+    ck.setupContext(mockWindow)
 
-    assert(mockWindow.__karma__ == null)
-    assert(mockWindow.onbeforeunloadK == null)
+    assert(mockWindow.onbeforeunload == null)
     assert(mockWindow.onerror == null)
   })
 
   it('should setup context if there was error but clearContext config is false', function () {
-    var config = {
+    var config = ck.config = {
       clearContext: false
     }
 
@@ -103,14 +108,32 @@ describe('Karma', function () {
 
     var mockWindow = {}
 
-    k.error('page reload')
-    k.setupContext(mockWindow)
+    ck.error('page reload')
+    ck.setupContext(mockWindow)
 
-    assert(mockWindow.__karma__ != null)
     assert(mockWindow.onbeforeunload != null)
     assert(mockWindow.onerror != null)
   })
 
+  it('should error out if a script attempted to reload the browser after setup', function () {
+    // Perform setup
+    var config = ck.config = {
+      clearContext: true
+    }
+    socket.emit('execute', config)
+    var mockWindow = {}
+    ck.setupContext(mockWindow)
+
+    // Spy on our error handler
+    sinon.spy(k, 'error')
+
+    // Emulate an unload event
+    mockWindow.onbeforeunload()
+
+    // Assert our spy was called
+    assert(k.error.calledWith('Some of your tests did a full page reload!'))
+  })
+
   it('should report navigator name', function () {
     var spyInfo = sinon.spy(function (info) {
       assert(info.name === 'Fake browser name')
@@ -127,7 +150,7 @@ describe('Karma', function () {
   it('should report browser id', function () {
     windowLocation.search = '?id=567'
     socket = new MockSocket()
-    k = new Karma(socket, {}, windowStub, windowNavigator, windowLocation)
+    k = new ClientKarma(socket, {}, windowStub, windowNavigator, windowLocation)
 
     var spyInfo = sinon.spy(function (info) {
       assert(info.id === '567')
@@ -148,12 +171,12 @@ describe('Karma', function () {
 
       // emit 49 results
       for (var i = 1; i < 50; i++) {
-        k.result({id: i})
+        ck.result({id: i})
       }
 
       assert(!spyResult.called)
 
-      k.result('result', {id: 50})
+      ck.result('result', {id: 50})
       assert(spyResult.called)
       assert(spyResult.args[0][0].length === 50)
     })
@@ -166,10 +189,10 @@ describe('Karma', function () {
 
       // emit 40 results
       for (var i = 1; i <= 40; i++) {
-        k.result({id: i})
+        ck.result({id: i})
       }
 
-      k.complete()
+      ck.complete()
       assert(spyResult.called)
       assert(spyResult.args[0][0].length === 40)
     })
@@ -188,7 +211,7 @@ describe('Karma', function () {
       setTransportTo('websocket')
 
       // adapter didn't call info({total: x})
-      k.result()
+      ck.result()
       assert.deepEqual(log, ['start', 'result'])
     })
 
@@ -208,8 +231,8 @@ describe('Karma', function () {
 
       setTransportTo('websocket')
 
-      k.info({total: 321})
-      k.result()
+      ck.info({total: 321})
+      ck.result()
       assert.deepEqual(log, ['start', 'result'])
       assert(spyStart.calledWith({total: 321}))
     })
@@ -217,7 +240,7 @@ describe('Karma', function () {
 
   describe('setupContext', function () {
     it('should capture alert', function () {
-      sinon.spy(k, 'log')
+      sinon.spy(ck, 'log')
 
       var mockWindow = {
         alert: function () {
@@ -225,9 +248,9 @@ describe('Karma', function () {
         }
       }
 
-      k.setupContext(mockWindow)
+      ck.setupContext(mockWindow)
       mockWindow.alert('What?')
-      assert(k.log.calledWith('alert', ['What?']))
+      assert(ck.log.calledWith('alert', ['What?']))
     })
   })
 
@@ -250,19 +273,22 @@ describe('Karma', function () {
 
       // emit 40 results
       for (var i = 0; i < 40; i++) {
-        k.result({id: i})
+        ck.result({id: i})
       }
 
       assert(!spyResult.called)
 
-      k.complete()
+      ck.complete()
       assert(spyResult.called)
     })
 
     it('should navigate the client to return_url if specified', function (done) {
       windowLocation.search = '?id=567&return_url=http://return.com'
       socket = new MockSocket()
-      k = new Karma(socket, {}, windowStub, windowNavigator, windowLocation)
+      k = new ClientKarma(socket, {}, windowStub, windowNavigator, windowLocation)
+      clientWindow = {karma: k}
+      ck = new ContextKarma(ContextKarma.getDirectCallParentKarmaMethod(clientWindow))
+      ck.config = {}
 
       sinon.spy(socket, 'disconnect')
 
@@ -270,7 +296,7 @@ describe('Karma', function () {
         ack()
       })
 
-      k.complete()
+      ck.complete()
 
       clock.tick(500)
       setTimeout(function () {
@@ -281,8 +307,8 @@ describe('Karma', function () {
     })
 
     it('should patch the console if captureConsole is true', function () {
-      sinon.spy(k, 'log')
-      k.config.captureConsole = true
+      sinon.spy(ck, 'log')
+      ck.config.captureConsole = true
 
       var mockWindow = {
         console: {
@@ -290,15 +316,15 @@ describe('Karma', function () {
         }
       }
 
-      k.setupContext(mockWindow)
+      ck.setupContext(mockWindow)
       mockWindow.console.log('What?')
-      assert(k.log.calledWith('log'))
-      assert(k.log.args[0][1][0] === 'What?')
+      assert(ck.log.calledWith('log'))
+      assert(ck.log.args[0][1][0] === 'What?')
     })
 
     it('should not patch the console if captureConsole is false', function () {
-      sinon.spy(k, 'log')
-      k.config.captureConsole = false
+      sinon.spy(ck, 'log')
+      ck.config.captureConsole = false
 
       var mockWindow = {
         console: {
@@ -306,20 +332,20 @@ describe('Karma', function () {
         }
       }
 
-      k.setupContext(mockWindow)
+      ck.setupContext(mockWindow)
       mockWindow.console.log('hello')
-      assert(!k.log.called)
+      assert(!ck.log.called)
     })
 
     it('should clear context window upon complete when clearContext config is true', function () {
-      var config = {
+      var config = ck.config = {
         clearContext: true
       }
 
       socket.emit('execute', config)
       var CURRENT_URL = iframe.src
 
-      k.complete()
+      ck.complete()
 
       // clock.tick() does not work in IE 7
       setTimeout(function () {
@@ -329,14 +355,14 @@ describe('Karma', function () {
     })
 
     it('should not clear context window upon complete when clearContext config is false', function () {
-      var config = {
+      var config = ck.config = {
         clearContext: false
       }
 
       socket.emit('execute', config)
       var CURRENT_URL = iframe.src
 
-      k.complete()
+      ck.complete()
 
       clock.tick(1)
 
diff --git a/test/client/stringify.spec.js b/test/client/stringify.spec.js
index ecd44d4b4..a2e8ea11e 100644
--- a/test/client/stringify.spec.js
+++ b/test/client/stringify.spec.js
@@ -1,7 +1,7 @@
 /* global __karma__ */
 var assert = require('assert')
 
-var stringify = require('../../client/stringify')
+var stringify = require('../../common/stringify')
 
 describe('stringify', function () {
   it('should serialize string', function () {
diff --git a/test/client/util.spec.js b/test/client/util.spec.js
index 88bd4fa31..035ffc49b 100644
--- a/test/client/util.spec.js
+++ b/test/client/util.spec.js
@@ -1,6 +1,6 @@
 var assert = require('assert')
 
-var util = require('../../client/util')
+var util = require('../../common/util')
 
 describe('util', function () {
   it('parseQueryParams', function () {