how to handle drag and pinch gesture in iOS

[Omar Reis]

I made a paperscript that handles onMouseDrag() event.

When I use it with Safari on iPhone, there is a problem:
Safari's pinch/scroll gestures doesn't work inside the script
if it implements the drag event. So if the user zooms the script to
full screen, she can not zoom out or scroll out.
The browser viewport gets stuck !

Two questions:

1- How can I tell between one finger drag
    and two finger pinch/scroll ? I would like to use the first
    and let the browser handle the former.

2- How can I pass the event on to the browser if I choose
  not to use it (for example, if the user clicks an empty area inside the script ?

thanks
Omar