0.0.6 • Public • Published

    Selenium Java Robot

    This repository contains a tool which allows JavaScript scripts running in a browser to generate keyboard and mouse events at the operating system level.

    This is especially useful when writing tests for your application, to simulate actions from the user.

    Installing this tool

    Before installing this tool, please make sure node.js, npm and Java are installed on your computer.

    Then, this tool can be installed with the following command line:

    npm install -g selenium-java-robot

    Command line usage

    Execute the selenium-java-robot command:


    Here is the list of accepted options:

    --browser <browserName>

    Replace <browserName> with the name of one of the following accepted browsers:

    • Firefox (default value, except on Mac OS)

    • Safari (default value on Mac OS)

    • Chrome or Chrome-debug (using Chrome-debug is much slower than using Chrome, but Chrome-debug allows DevTools to be open, where as Chrome does not support it, see here for a technical explanation)

    • Internet Explorer

    --url <initialUrl>

    Replace <initialUrl> with the URL to initially load in the browser. The default URL is http://localhost:7777/__attester__/slave.html which corresponds to the default URL of attester, when running it locally.


    This option makes sure the browser is automatically restarted in case it is closed. The browser is restarted at the URL specified by the --url parameter.


    If this option is present, the list of accepted options is displayed and the Selenium Java Robot exits without starting a browser.


    If this option is present, the version of the Selenium Java Robot is displayed and the Selenium Java Robot exits without starting a browser.


    This option allows to set a Java system property before launching the browser. This parameter can be repeated multiple times to set different properties. Different Selenium drivers use different Java system properties. Please refer to the corresponding documentation:


    Once the Selenium Java Robot starts, it first tries to detect the position of the viewport inside the browser window by displaying a calibration page and taking a screenshot to detect the coordinates of the page. This is done automatically. This process can sometimes fail if the browser window is hidden by another window.

    Once this is done, the browser automatically navigates to the URL specified in the command line.

    JavaScript API

    Inside the page loaded by the Selenium Java Robot, an object called SeleniumJavaRobot is automatically made available. It contains some methods which can be called to simulate keyboard and mouse events.


    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. Note that most of those methods are simply a bridge to the corresponding method in the Java Robot.

    • getOffset (callback: Callback)

    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.

    How to recompile this tool

    Before compiling this tool, you need a Java JDK and Maven to be installed on your computer.

    Then you can simply execute the following command from the root directory of your clone of this repository:

    npm install

    This will install dependencies and compile the Selenium Java Robot tool.

    How it is implemented

    Selenium is used to start the web browser and to communicate with it.

    The Java Robot class is used to send keyboard and mouse events to the operating system, and to perform the screen capture for the calibration.

    For more information about the implementation, do not hesitate to have a look at the source code in this repository.


    Apache License 2.0




    npm i selenium-java-robot

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