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    2.3.0 • Public • Published

    NPM Version Dependencies Reactive Programming

    On-screen keyboard detector

    Indirect detection of the presence of the on-screen keyboard (OSK) shown by mobile browsers when the user interacts with input controls on a webpage.


    This approach employs the browsers layout and visual viewports (Explainer, MDN, Demo) to observe the appearance of the virtual keyboard.

    Simplified, since it's introduction

    • Mobile Safari excludes the keyboard from the visual viewport, while
    • Chrome for Android the keyboard is excluded from both the visual and the layout viewport.

    Browser Viewports

    Chrome's behaviour makes it necessary to also observe focusin, focusout, resize and visibilitychange events.


    The indirect detection relying on viewport and window DOM events brings some limitations:

    • hidden and visible events are dispatched with a approximate 1 second delay.
    • On Chrome for Android the keyboard must be initially hidden when subscribing to the detector.
    • On iOS requires Safari v. ≥ 13
    • On iPad the predictive text bar, which is shown when an external keyboard is used, is not detected as visible keyboard.

    iPad Predictive Text Bar

    Because of these caveats, the straight-forward way of detecting blur and focus events on inputs should be explored before falling back on this project.


    npm install on-screen-keyboard-detector



    import { subscribe, isSupported } from 'on-screen-keyboard-detector';
    if (isSupported()) {
    	const unsubscribe = subscribe(visibility => {
    		if (visibility === "hidden") {
    			// ...
    		else { // visibility === "visible"
    			// ...
    	// After calling unsubscribe() the callback will no longer be invoked.


    subscribe(listenerCallback): unsubscribe

    Begins to observe browser events and invokes the provided callback function when a change in the keyboard visibility is detected.

    Parameter Type Description
    callback function(String) user-defined handler which receives the keyboard visibility changes

    Return value

    function(): void : Unsubscribes to receive updates


    Returns true if the browser runtime supports oskd.

    Advanced Usage

    Multiple Subscriptions (PubSub)

    PubSub is not part of this module and needs additional tools, e.g. emittery. See demo/pubsub.html

    import {subscribe} from 'on-screen-keyboard-detector';
    import Emitter from 'emittery';
    const emitter = new Emitter();
    subscribe(visibility => emitter.emit(visibility));
    emitter.on('hidden', function() { /* ... */ });
    emitter.on('visible', function() { /* ... */ });


    Requirements (not listed in package.json)

    • mocha
    • chai 🍵
    • selenium-webdriver
    • a Mac for Mobile Safari tests
    • running a local webserver (see TEST_SERVER in package.json), E.g. run http-server in the project root folder http-server . --port 8081


    For real devices make sure

    • the adb server is running (adb start-server), and
    • a device is connected via USB or Wifi (adb devices -l)
    • ggf. adb tcpip 5555 and adb connect <test phone ip address> (see "setup_test" in package.json) Then run npm run test:chrome.


    Connect a device where Remote Automatation is enabled for Safari (see the Webkit blog). Then run npm run test:ios

    iOS tests should be performed manually (see the demo folder), because Webdriver controlled Mobile Safari does not show the virtual keyboard


    Ramda, and Most for the reactive functional infrastructure.

    Changelog (See changelog.md)


    npm i on-screen-keyboard-detector

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    • semmel