diff --git a/lib/capybara/webkit/browser.rb b/lib/capybara/webkit/browser.rb
index 8aac793..6a8c426 100644
--- a/lib/capybara/webkit/browser.rb
+++ b/lib/capybara/webkit/browser.rb
@@ -134,7 +134,7 @@ module Capybara::Webkit
     end
 
     def get_window_handles
-      JSON.parse(command('GetWindowHandles'))
+      JSON.parse(command("GetWindowHandles"))
     end
 
     def window_handles
@@ -144,7 +144,7 @@ module Capybara::Webkit
     end
 
     def get_window_handle
-      command('GetWindowHandle')
+      command("GetWindowHandle")
     end
 
     def window_handle
@@ -236,12 +236,17 @@ https://github.com/thoughtbot/capybara-webkit/wiki/Reporting-Crashes
     end
 
     def evaluate_script(script, *args)
-      json = command('Evaluate', script, args.to_json)
+      json = command("Evaluate", script, args.to_json)
+      JSON.parse("[#{json}]").first
+    end
+
+    def evaluate_async_script(script, *args)
+      json = command("EvaluateAsync", script, args.to_json)
       JSON.parse("[#{json}]").first
     end
 
     def execute_script(script, *args)
-      command('Execute', script, args.to_json)
+      command("Execute", script, args.to_json)
     end
 
     def render(path, width, height)
diff --git a/lib/capybara/webkit/driver.rb b/lib/capybara/webkit/driver.rb
index a659489..951cc4a 100644
--- a/lib/capybara/webkit/driver.rb
+++ b/lib/capybara/webkit/driver.rb
@@ -91,6 +91,11 @@ module Capybara::Webkit
       decode_result(result)
     end
 
+    def evaluate_async_script(script, *args)
+      result = @browser.evaluate_async_script(script, *encode_args(args))
+      decode_result(result)
+    end
+
     def console_messages
       @browser.console_messages
     end
diff --git a/spec/driver_spec.rb b/spec/driver_spec.rb
index f6b1326..1f93038 100644
--- a/spec/driver_spec.rb
+++ b/spec/driver_spec.rb
@@ -554,12 +554,11 @@ describe Capybara::Webkit::Driver do
 
     it "evaluates Javascript and returns an object" do
       result = driver.evaluate_script(%<({ 'one' : 1 })>)
-      expect(result).to eq 'one' => 1
+      expect(result).to eq "one" => 1
     end
 
     it "evaluate Javascript and returns an object when the original was readonly" do
       result = driver.evaluate_script(%<window.getComputedStyle(document.getElementById('greeting'))>)
-      # result = driver.evaluate_script(%<document.getElementById('greeting')>)
       expect(result).to be_a Hash
       expect(result["zIndex"]).to eq "auto"
     end
@@ -584,6 +583,27 @@ describe Capybara::Webkit::Driver do
       expect(result).to eq [1, 2]
     end
 
+    it "evaluates asynchronous JS which isn't" do
+      result = driver.evaluate_async_script("arguments[0](4)")
+      expect(result).to eq 4
+    end
+
+    it "evaluates asynchronous JS" do
+      result = driver.evaluate_async_script("setTimeout(function(callback){ callback('jaguar') }, 100, arguments[0])")
+      expect(result).to eq "jaguar"
+    end
+
+    it "evaluates asynchronous JS and returns an object" do
+      result = driver.evaluate_async_script(%<setTimeout(function(callback){ callback({ 'one' : 1 }) }, 100, arguments[0])>)
+      expect(result).to eq "one" => 1
+    end
+
+    it "evaluates asynchronous JS and returns an object when the original was readonly" do
+      result = driver.evaluate_async_script(%<setTimeout(function(callback){ callback(window.getComputedStyle(document.getElementById('greeting'))) }, 100, arguments[0])>)
+      expect(result).to be_a Hash
+      expect(result["zIndex"]).to eq "auto"
+    end
+
     it "executes Javascript" do
       driver.execute_script(%<document.getElementById('greeting').innerHTML = 'yo'>)
       expect(driver.find_xpath("//p[contains(., 'yo')]")).not_to be_empty
@@ -612,6 +632,12 @@ describe Capybara::Webkit::Driver do
       expect(driver.find_xpath("//p[@id='greeting'][contains(., 'new content')]")).not_to be_empty
     end
 
+    it "passes elements as arguments to asynchronous script" do
+      greeting = driver.find_xpath("//p[@id='greeting']").first
+      result = driver.evaluate_async_script(%<arguments[2]([arguments[1], arguments[0]])>, greeting, "a string")
+      expect(result).to eq ["a string", greeting]
+    end
+
     it "passes arguments to evaaluated Javascript" do
       expect(driver.evaluate_script(%<arguments[0]>, 3)).to eq 3
     end
diff --git a/spec/server_spec.rb b/spec/server_spec.rb
index 9b208b1..9d203a4 100644
--- a/spec/server_spec.rb
+++ b/spec/server_spec.rb
@@ -2,7 +2,8 @@ require "spec_helper"
 require "capybara/webkit/server"
 
 describe Capybara::Webkit::Connection do
-  it "ensures the process ends", skip_on_windows: true, skip_on_jruby: true do
+  it "ensures the process ends when the parent process ends", skip_on_windows: true, skip_on_jruby: true do
+    sleep 1 # Without this sleep popen3 hangs on OSX when running the tests - not really sure why
     read_io, write_io = IO.pipe
 
     fork_pid = fork do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 4ae1332..8b3a3d2 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -13,7 +13,7 @@ $webkit_server = Capybara::Webkit::Server.new
 $webkit_connection = Capybara::Webkit::Connection.new(server: $webkit_server)
 $webkit_browser = Capybara::Webkit::Browser.new($webkit_connection)
 
-if ENV['DEBUG']
+if ENV["DEBUG"]
   $webkit_browser.enable_logging
 end
 
@@ -61,6 +61,9 @@ RSpec.configure do |c|
      end
     )
   }
+
+  c.filter_run :focus unless ENV["TRAVIS"]
+  c.run_all_when_everything_filtered = true
 end
 
 def with_env_vars(vars)
diff --git a/src/CommandFactory.cpp b/src/CommandFactory.cpp
index 546630a..26ce2f4 100644
--- a/src/CommandFactory.cpp
+++ b/src/CommandFactory.cpp
@@ -5,6 +5,7 @@
 #include "Reset.h"
 #include "Node.h"
 #include "Evaluate.h"
+#include "EvaluateAsync.h"
 #include "Execute.h"
 #include "FrameFocus.h"
 #include "Header.h"
diff --git a/src/Evaluate.cpp b/src/Evaluate.cpp
index 61bcd94..9ee72fe 100644
--- a/src/Evaluate.cpp
+++ b/src/Evaluate.cpp
@@ -18,8 +18,8 @@ void Evaluate::start() {
   QString eval_script = QString("(function(){"
                            "   for(var i=0; i<arguments.length; i++) {"
                            "     arguments[i] = JSON.parse(arguments[i]);"
-                           "     var elem_id;"
-                           "     if (elem_id = arguments[i]['element-581e-422e-8be1-884c4e116226']) {"
+                           "     var elem_id = arguments[i]['element-581e-422e-8be1-884c4e116226'];"
+                           "     if (elem_id) {"
                            "       arguments[i] = Capybara.getNode(elem_id);"
                            "     };"
                            "   };"
diff --git a/src/EvaluateAsync.cpp b/src/EvaluateAsync.cpp
new file mode 100644
index 0000000..f4735bf
--- /dev/null
+++ b/src/EvaluateAsync.cpp
@@ -0,0 +1,54 @@
+#include "EvaluateAsync.h"
+#include "WebPage.h"
+#include "WebPageManager.h"
+#include "JsonSerializer.h"
+#include <iostream>
+
+EvaluateAsync::EvaluateAsync(WebPageManager *manager, QStringList &arguments, QObject *parent) : SocketCommand(manager, arguments, parent) {
+}
+
+void EvaluateAsync::start() {
+  QString script = arguments()[0];
+  QString jsonArgs;
+  if (arguments().length()>1){
+    jsonArgs = arguments()[1];
+  } else {
+    jsonArgs ="[]";
+  }
+  QString eval_script = QString("(function(){"
+                           "   for(var i=0; i<arguments.length-1; i++) {"
+                           "     arguments[i] = JSON.parse(arguments[i]);"
+                           "     var elem_id = arguments[i]['element-581e-422e-8be1-884c4e116226'];"
+                           "     if (elem_id) {"
+                           "       arguments[i] = Capybara.getNode(elem_id);"
+                           "     };"
+                           "   };"
+                           "   eval(\"%1\");"
+                           "   return;"
+                           " }).apply(null, %2.concat(function(res){ "
+                           " res = Capybara.wrapResult(res);"
+                           // This isn't necessary in Qt 5.5 but is in older (at least 5.2 on Travis)
+                           " if (res instanceof Array) {"
+                           "    CapybaraAsync['asyncResult(QVariantList)'](res);"
+                           " } else { "
+                           "    CapybaraAsync['asyncResult(QVariant)'](res);"
+                           " }"
+                           " }))").arg(script.replace("\"","\\\"").remove("\n"), jsonArgs);
+  QObject invocation_stub;
+  invocation_stub.setProperty("allowUnattached", false);
+  page()->currentFrame()->addToJavaScriptWindowObject("CapybaraInvocation", &invocation_stub);
+  page()->currentFrame()->addToJavaScriptWindowObject("CapybaraAsync", this);
+  page()->currentFrame()->evaluateJavaScript(eval_script);
+}
+
+void EvaluateAsync::asyncResult(QVariantList result) {
+  JsonSerializer serializer;
+  finish(true, serializer.serialize(result));
+}
+
+void EvaluateAsync::asyncResult(QVariant result) {
+  JsonSerializer serializer;
+  finish(true, serializer.serialize(result));
+}
+
+
diff --git a/src/EvaluateAsync.h b/src/EvaluateAsync.h
new file mode 100644
index 0000000..9433054
--- /dev/null
+++ b/src/EvaluateAsync.h
@@ -0,0 +1,14 @@
+#include "SocketCommand.h"
+
+#include <QVariantList>
+
+class EvaluateAsync : public SocketCommand {
+  Q_OBJECT
+
+  public:
+    EvaluateAsync(WebPageManager *, QStringList &arguments, QObject *parent = 0);
+    virtual void start();
+    Q_INVOKABLE void asyncResult(QVariant result);
+    Q_INVOKABLE void asyncResult(QVariantList result);
+};
+
diff --git a/src/find_command.h b/src/find_command.h
index 72e04e3..559e977 100644
--- a/src/find_command.h
+++ b/src/find_command.h
@@ -8,6 +8,7 @@ CHECK_COMMAND(FindXpath)
 CHECK_COMMAND(Reset)
 CHECK_COMMAND(Node)
 CHECK_COMMAND(Evaluate)
+CHECK_COMMAND(EvaluateAsync)
 CHECK_COMMAND(Execute)
 CHECK_COMMAND(FrameFocus)
 CHECK_COMMAND(Header)
diff --git a/src/webkit_server.pro b/src/webkit_server.pro
index bd0787b..7bb7b0c 100644
--- a/src/webkit_server.pro
+++ b/src/webkit_server.pro
@@ -47,6 +47,7 @@ HEADERS = \
   Node.h \
   JavascriptInvocation.h \
   Evaluate.h \
+  EvaluateAsync.h \
   Execute.h \
   FrameFocus.h \
   Response.h \
@@ -132,6 +133,7 @@ SOURCES = \
   Node.cpp \
   JavascriptInvocation.cpp \
   Evaluate.cpp \
+  EvaluateAsync.cpp \
   Execute.cpp \
   FrameFocus.cpp \
   Response.cpp \