Puede usar Fileopenpicker en su código JS de esta manera:

 var openPicker = new Windows.Storage.Pickers.FileOpenPicker(); openPicker.viewMode = Windows.Storage.Pickers.PickerViewMode.thumbnail; openPicker.suggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.picturesLibrary; // Users expect to have a filtered view of their folders depending on the scenario. // For example, when choosing a documents folder, restrict the filetypes to documents for your application. openPicker.fileTypeFilter.replaceAll([".png", ".jpg", ".jpeg"]); // Open the picker for the user to pick a file openPicker.pickSingleFileAsync().then(function (file) { if (file) { // Application now has read/write access to the picked file WinJS.log && WinJS.log("Picked photo: " + file.name, "sample", "status"); } else { // The picker was dismissed with no selected file WinJS.log && WinJS.log("Operation cancelled.", "sample", "status"); } });

Lo que necesita es cambiar el tipo de archivo al tipo de destino que necesita.

Hay una muestra de JS a la que puede referirse directamente: FilePicker - JS .