Add to home screen allows websites and PWA's to work like native apps without registering in the Apple or Google App Stores. Currently, it is very difficult to get users to add web apps to their home screen, limiting the utility of such websites compared to native apps. See related Medium blog post.
This drop-in JS Library for websites effectively guides a user to add the website to their home screen on IOS, Android and Desktop.
Instructions and UI in this library have been "battle-tested" and has yielded an ~85% home screen install rate on IOS and Android across all ages in past implementations.
Here is a demo (please open on your phone) of library use within a hypothetical app "Aardvark" 
All major browsers on IOS/Android/Desktop are supported. Here are the guides shown for each platform/browser:
Users are guided to open the link in the system browser.
Make sure your site has the minimum requirements for installing a web app on homescreen for IOS and Android and Desktop.
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At
https://your-website.com/apple-touch-icon.png, include a square icon of your app that is (1) at least 40 x 40 pixels and (2) specifically namedapple-touch-icon.png(example). -
At
https://your-website.com/manifest.json, include a web manifest filemanifest.json(example). Reference the manifest in your index HTML file.index.html<head> ... <link rel="manifest" crossorigin="use-credentials" href="manifest.json" /> .. </head>
This should be a quick drop-in library into your website.
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Include the library JavaScript and CSS files in your header (You can use JSDelivr CDN if you're just using the library directly and not making any changes):
index.html<head> ... <link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/philfung/add-to-homescreen@2.2/dist/add-to-homescreen.min.css" /> <script src="https://cdn.jsdelivr.net/gh/philfung/add-to-homescreen@2.2/dist/add-to-homescreen.min.js"></script> ... </head>
The code above will include a JavaScript file containing all the available translations for the locales this library supports. It is highly optimized to be small and quick to deliver over mobile networks. If however you want to be even more highly optimized, the library also has JavaScript files built with just a single locale of translations, which is about 60% smaller.
For example, the Spanish file
add-to-homescreen_es.min.jscan be included as below. If you have a dynamic server environment and know the user's preferred locale, this can be a good option. To see all the supported locales, look in thedistfolder.<head> ... <link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/philfung/add-to-homescreen@2.2/dist/add-to-homescreen.min.css" /> <script src="https://cdn.jsdelivr.net/gh/philfung/add-to-homescreen@2.2/dist/add-to-homescreen_es.min.js"></script> ... </head>
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Call the library onload.
index.html<script> document.addEventListener('DOMContentLoaded', function () { window.AddToHomeScreenInstance = window.AddToHomeScreen({ appName: 'Aardvark', // Name of the app. // Required. appNameDisplay: 'standalone', // If set to 'standalone' (the default), the app name will be diplayed // on it's own, beneath the "Install App" header. If set to 'inline', the // app name will be displayed on a single line like "Install MyApp" // Optional. Default 'standalone' appIconUrl: 'apple-touch-icon.png', // App icon link (square, at least 40 x 40 pixels). // Required. assetUrl: 'https://cdn.jsdelivr.net/gh/philfung/add-to-homescreen@2.2/dist/assets/img/', // Link to directory of library image assets. maxModalDisplayCount: -1 // If set, the modal will only show this many times. // Optional. Default: -1 (no limit). (Debugging: Use this.clearModalDisplayCount() to reset the count) }); ret = window.AddToHomeScreenInstance.show('en'); // show "add-to-homescreen" instructions to user, or do nothing if already added to homescreen // The only argument is the language to show the messages in (currently only 'da', 'de', 'en', 'es', 'fr', 'he', 'it', 'pt' and 'ru' are available). }); </script> </body>
Here's an example implementation.
2-alternate. if you're calling the UI NOT onload, but sometime after (for example, in an onclick() handler for an "Install App" button), then you should still create your the instance onload, but call your UI later on the instance variable with .show()):
index.html
<script>
document.addEventListener('DOMContentLoaded', function () {
window.AddToHomeScreenInstance = window.AddToHomeScreen({...
}));
document.getElementById('my_install_app_button').addEventListener('click', function () {
window.AddToHomeScreenInstance.show('en');
});
</script>
</body>This is because some handlers must be created onload.
AddToHomescreen builds multiple copies of the library, all to the dist folder, each with their own intended usage.
The most likely JavaScript file that you'll use is add-to-homescreen.min.js. This is the minified production read code.
If you are debugging a change you made to the library, the add-to-homescreen.js file is an unminified version of the code, which you can use by loading the /debug path in the server below.
The library also builds multiple other copies of the JavaScript code that are specific to an individual locale, for
example add-to-homescreen_es.min.js only contains the Spanish translations. These are intended to be used by
applications that are highly concerned with the amount of JavaScript code that is downloaded on a mobile device, and they
are generally less than half the size of the default file. If your server is aware of the desired locale and you have the
ability to change what file is loaded at page load time, these files can be a good choice.
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Make changes
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Build the library into the
distdirectorynpm install npm run buildThis will build all variations of the JavaScript file and start a server for your testing. 3. Test locally:
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Start local server
npm run build npm run startLoad an example page http://127.0.0.1:8081, or load an example page with unminified code at http://127.0.0.1:8081/debug
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Save the dist directory to a CDN of your choice. Follow the steps in the previous section.
No dependencies. This is written in raw ES6 javascript and all css is namespaced to minimize codebase conflict and bloat.
