App Helper Script

Updated on 27. December 2022 by Jan Bunk

We have created a JavaScript script file with a couple of useful helper functions that simplify the communication between your website and your app.


You can either copy the script (or parts of it) and host it yourself, or load it directly from our website.

View the app helper script

<script src=""></script>

The script is minified, but not obfuscated, so you can use a javascript formatter/beautifier if you want to take a look at the functions' implementations.



After every page load the app first needs to inject some javascript into the loaded page. This is to allow your website to call javascript functions like setNotificationTopicSubscriptionStatus. Unfortunately, this is not instant, so if you try to call a javascript function that interacts with the app really quickly after the page load, they might not be defined yet.

You can avoid this by wrapping the code that interacts with your app in a call to executeWhenAppReady.

When your website is loaded using a browser, the code inside executeWhenAppReady will not be executed. This means you can also use this function to detect whether your website was loaded by the app or a browser. Other methods for that are explained here.

    // setNotificationTopicSubscriptionStatus interacts with the app, so it won't immediately be available after a new page was loaded
    executeWhenAppReady(function () {
        console.log("Website was loaded by the app and the app is ready for interaction");

        // by running inside a executeWhenAppReady call, we avoid potentially calling it while still undefined
        setNotificationTopicSubscriptionStatus(true, "new-games");
    // remember to make the function async if you use await inside it!
    // getSubscribedNotificationTopics also interacts with the app and returns a result that needs to be awaited
    executeWhenAppReady(async function () {
        var topics = (await getSubscribedNotificationTopics())["topics"];


You can use this function to find out on what operating system the current user is using the app.

This function doesn't need to be wrapped inside executeWhenAppReady. It can also be used to check if the current user is using the app (check that the returned value is not null). This does not guarantee that the app is ready for JavaScript interaction yet though. If you want to call JavaScript functions that interact with the app, you should still wrap them in executeWhenAppReady.

    // possible return values are:
    // "android"
    // "ios"
    // null -> not using app, most likely a regular browser
    var platform = getAppPlatform();
This function relies on checking user agents, so it only works if you have configured the app to adjust the user agent it uses. You can enable this option in your app's navigation settings. Open Navigation Settings

isInCustomTab, getCustomTabData, closeCustomTab

These functions are used for managing custom tabs.