Generate a unique integer id (unique within the entire client session).
        Useful for temporary DOM ids.

def uniqueId(self, prefix=""):
        """
        Generate a unique integer id (unique within the entire client session).
        Useful for temporary DOM ids.
        """
        _IdCounter.count += 1
        id = _IdCounter.count
        if prefix:
            return self._wrap(prefix + str(id))
        else:
            return self._wrap(id)