ProximityDevice.PublishBinaryMessage | publishBinaryMessage methods

 var proximityDevice;

    function publishLaunchApp() {
 proximityDevice = Windows.Networking.Proximity.ProximityDevice.GetDefault();

    if (proximityDevice) {
     // The format of the app launch string is: "<args>\tWindows\t<AppName>".
     // The string is tab or null delimited.

     // The <args> string can be an empty string ("").
     var launchArgs = "user=default";

     // The format of the AppName is: PackageFamilyName!PRAID.
     var praid = "MyAppId"; // The Application Id value from your package.appxmanifest.

     var appName = Windows.ApplicationModel.Package.current.id.familyName + "!" + praid;

     var launchAppMessage = launchArgs + "\tWindows\t" + appName;

     var dataWriter = new Windows.Storage.Streams.DataWriter();
     dataWriter.unicodeEncoding = Windows.Storage.Streams.UnicodeEncoding.utf16LE;
     dataWriter.writeString(launchAppMessage);
     var launchAppPubId =
          proximityDevice.publishBinaryMessage(
              "LaunchApp:WriteTag", 
              dataWriter.detachBuffer());
 }
    }