Tool allowing JavaScripts scripts running in a browser to send keyboard and mouse events to the Virtual Box machine they run in, especially for automated tests.

Usage no npm install needed!

<script type="module">
  import vboxRobot from 'https://cdn.skypack.dev/vbox-robot';


vbox-robot server

This repository contains a tool which starts an HTTP server and accepts requests to clone and start Virtual Box virtual machines, to stop and delete them and to run programs in them. It also offers a browser JavaScript API to control the keyboard and mouse inside the connected virtual machines.

The JavaScript API to control the keyboard and mouse in the virtual machines is the same as the one provided by the Selenium Java Robot, and the Robot Server, but the implementation is completely different, as it relies on the Virtual Box API, which generates keyboard and mouse events at the lowest possible level.

Combined with attester and attester-launcher, vbox-robot can be used to automate the testing of web applications, and how they react to specific user input. Especially, it allows to automatically test the compatibility of web applications with screen readers, even if they modify the behavior of the keyboard at a low level in the operating system.

Installing this tool

Before installing this tool, please make sure node.js and npm are installed on your computer. Virtual Box can be installed either on the same computer or on a different one.

This tool can then be installed with the following command line:

npm install -g vbox-robot

Command line usage

  • Make sure VBoxWebSrv, from the Virtual Box installation, is running.

For example, on Windows, you can run the following command:

"%VBOX_MSI_INSTALL_PATH%\VBoxWebSrv.exe" --authentication null

The --authentication null option disables authentication for simplicity, but this should be done with caution. You can explore the options of VBoxWebSrv with the --help option.

  • Now that VBoxWebSrv is running, it is possible to execute the vbox-robot command:
vbox-robot --username toto --password secret

This command opens a web server on port 7778 (by default).

The --username and --password options allow to specify a user name and password to protect the root url of the web server with basic authentication. Other URLs of the HTTP API are not protected with basic authentication, but they contain an id in the URL which cannot be easily guessed.

vbox-robot connects by default to the VBoxWebSrv process running on the same machine with the default port, but the --vboxwebsrv option allows to connect to a different URL.

You can see the list of accepted options with:

vbox-robot --help


Connecting to an already running virtual machine


curl -X POST 'http://toto:secret@localhost:7778/' -d '{"connect":"MyMachineName"}'

Sample return value:

    "robotjs" : "http://localhost:7778/vm/1-1452787263159-d0cd6cf022b981c1/robot.js",
    "run" : "http://localhost:7778/vm/1-1452787263159-d0cd6cf022b981c1/run",
    "close" : "http://localhost:7778/vm/1-1452787263159-d0cd6cf022b981c1/close"

The returned JSON object contains URLs which can be used to further interact with the virtual machine.

Cloning and starting a virtual machine


curl -X POST 'http://toto:secret@localhost:7778/' -d '{"clone":"MyMachineName", "snapshot": "MySnapshotName"}'

Sample return value:

    "robotjs" : "http://localhost:7778/vm/2-1452787433599-d6972233187fb4e9/robot.js",
    "run" : "http://localhost:7778/vm/2-1452787433599-d6972233187fb4e9/run",
    "close" : "http://localhost:7778/vm/2-1452787433599-d6972233187fb4e9/close"

The returned JSON object contains URLs which can be used to further interact with the virtual machine.

Running a command inside a virtual machine


curl -X POST 'http://localhost:7778/vm/2-1452787433599-d6972233187fb4e9/run' -d '{"commandLine": ["c:\\windows\\system32\\ping.exe", "-n", "1", "www.google.fr"], "user": "IEUser", "password": "Passw0rd!"}'

Sample return value:

    "stdout" : "\r\nPinging www.google.fr [] with 32 bytes of data:\r\nReply from bytes=32 time=18ms TTL=54\r\n\r\nPing statistics for\r\n    Packets: Sent = 1, Received = 1, Lost = 0 (0% loss),\r\nApproximate round trip times in milli-seconds:\r\n    Minimum = 18ms, Maximum = 18ms, Average = 18ms\r\n",
    "stderr" : "",
    "exitCode" : 0

Closing a virtual machine


curl -X POST 'http://localhost:7778/vm/2-1452787433599-d6972233187fb4e9/close'
  • If the machine was already running when vbox-robot connected to it, this command will only disconnect vbox-robot from it.

  • If the machine was cloned and started by vbox-robot, this command will stop and delete it.

JavaScript API

Once vbox-robot is loaded, and it is connected to a virtual machine, it is possible to use its API from a web page by including a script tag similar to the following one (the exact url is returned in the robotjs field of the action which connected vbox-robot to the corresponding virtual machine):

<script src="http://localhost:7778/vm/2-1452787433599-d6972233187fb4e9/robot.js"></script>

The script tag creates a JavaScript global object called SeleniumJavaRobot. (This name is used for compatibility with the Selenium Java Robot) This object contains some methods which can be called to simulate keyboard and mouse events in the corresponding virtual machine.

If you remove /robot.js at the end of the robot.js URL, you get the URL of a web page that you can open in a web browser in the virtual machine, which allows you to play with the different commands of the JavaScript API.


Each method on the SeleniumJavaRobot object accepts a callback as its last parameter, to be notified when the corresponding operation is done. When the callback is provided (which is optional), it is expected to be either a simple function, or an object with the following structure:

   fn: function (response, args) { /* ... */ }, // function to be called when the operation is done.
   scope: window, // object to be available as this in the callback function
   args: { /* something */ } // second argument passed to the callback function

Here is the structure of the response object passed in the callback as the first argument:

   success: true, // true if there was no problem during the execution of the method, false otherwise
   result: null // if success is true, this is the result of the method (currently only relevant for getOffset)
   // if success is false, result contains a string with the error message

List of methods

You can find in this section the description of the methods available on the SeleniumJavaRobot object.

  • getOffset (callback: Callback)

This method triggers a calibration of the robot and then returns the coordinates of the top left corner of the viewport in the screen, as detected during the calibration phase.

   fn: function (response) {
      if (response.success) {
         var coordinates = response.result;
         alert("The coordinates of the viewport in the screen are: " + coordinates.x + "," + coordinates.y);
  • mouseMove (x: Number, y: Number, callback: Callback)

Instantly moves the mouse to the specified x, y screen coordinates.

  • smoothMouseMove (fromX: Number, fromY: Number, toX: Number, toY: Number, duration: Number, callback: Callback)

Instantly moves the mouse to the specified fromX, fromY screen coordinates, then smoothly moves the mouse from there to the toX, toY screen coordinates. The duration of the move must be expressed in milliseconds.

  • mousePress (buttons: Number, callback: Callback)

Presses one or more mouse buttons. The mouse buttons should be released using the mouseRelease method. The buttons parameter can be a combination (with the logical OR operator a | b) of one or more of the following flags:

var BUTTON1_MASK = 16;
var BUTTON2_MASK = 8;
var BUTTON3_MASK = 4;

For example, to press both the button 1 and button 2 of the mouse at the same time, call:

SeleniumJavaRobot.mousePress(16 | 8);
  • mouseRelease (buttons: Number, callback: Callback)

Releases one or more mouse buttons.

  • mouseWheel (amount: Number, callback: Callback)

Rotates the scroll wheel on wheel-equipped mice.

The amount parameter is the number of "notches" to move the mouse wheel Negative values indicate movement up/away from the user, positive values indicate movement down/towards the user.

  • keyPress (keyCode: Number, callback: Callback)

Presses a given key. The key should be released using the keyRelease method. Valid key codes are the constants starting with VK_ as listed in this Java documentation.

  • keyRelease (keyCode: Number, callback: Callback)

Releases a given key.

  • type (text: String, callback: String)

Send multiple keys, as specified in the given text, one after the other. Note that this last method is not present in the API of the Selenium Java Robot, and the Robot Server.


Apache License 2.0