Accessing a Webpage

In Share extensions (on both platforms) and Action extensions (iOS only), you can give users access to web content by asking Safari to run a JavaScript file and return the results to the extension.

On both platforms, your custom JavaScript class can define a run() function that Safari invokes as soon as it loads the JavaScript file. In the run() function, Safari provides an argument named completionFunction, with which you can pass results to your app extension in the form of a key-value object. In iOS, you can also define a finalize() function that Safari invokes when your app extension calls completeRequestReturningItems:completion: at the end of its task. A finalize() function can use items your extension passes in completeRequestReturningItems:completion: to change the webpage as desired.

Create a JavaScript file that includes a global object named ExtensionPreprocessingJS. Assign a new instance of your custom JavaScript class to this object.