Opens a standard Open File dialog so that the user could select files for upload.
$au.imageUploaderFlash('uploaderID').uploadPane().addFiles();
This dialog supports multiple selection and all restrictions configured in the uploader are supported. In other words, it works in the same way as if the user clicks the Add Files button.
Note, due to the restrictions of HTML5, it may open a dialog only from a button click handler. If you call this method from any other place in your JavaScript code, it will be ignored.