iOS App UIWebView

We currently have an android app which is simply a WebView which loads a URL on our server: [login to view URL] We want to use the same method to create an iOS app, basically an UIWebView and splash screen that's it. UIWebView will load our remote server URL at startup. The problem is the html page includes a file upload field which allows users to select music tracks and upload to server, this is works perfectly on Andriod without any extra coding, but this function obviously not supported by iOS. Therefore we need you to create native function which we can call with Javascript when user presses the Choose File button. After pressing the button there should be a dialog where users can select a music on their phone. After choosing a music file the app should make a POST request with the file to our webpage along with a progress bar. And the UIWebView should display the result returned by the webpage. We also need some native functions which we can call with Javascript, including open URL in Safari, something similar to the Share Intent and a function to save music from HTTP to user's phone. So basically 4 functions which can be called by Javascript inside UIWebView: 1. Music upload - select music track and make POST to server with UIWebView 2. Open URL in Safari 3. Share plain text Intent with other Apps 4. Download music from URL to user's phone(MP3)