I have a phonegap app and I want to execute Javascript code in a background task. When the application enters background I start executing a javascript function which takes data out of a web database and sends some values to a web service, the returning data may toggle a push-notification to the user.
I found either how to call javascript from Objective-C here on Stackoverflow and how to implement Long-Running Background Tasks in the iOS SDK Documentation pages, but I haven’t found anything in combining both (what I think is e.g.: When I invoke javascript code via a webview, does this View even exist when the App is in background?) so I want to ask some more experienced iOS Developers if this is even possible.
I don’t think its really possible. Javascript requires a UIwebview to run (in realtime) and must be visible to the user. When an app is put in background only a small amount of tasks are allowed to run- webview not one of them.
Your better off sending your data to a web server that runs a cron-job or similar to send out a push notification via apples push notification server – You can also bypass this and use a service like http://urbanairship.com/