function(event) {
            // don't handle multi-touch
            if (event.touches && event.touches.length > 1) {
              return;
            }
            tl = t0 = buildTouchInfo('touchstart', getCoordinates(event));
            $movementTarget.on(moveEvents, onTouchMove);
            $movementTarget.on(endEvents, onTouchEnd);
            if (cancelEvents) {
              $movementTarget.on(cancelEvents, onTouchCancel);
            }
            if (startEventHandler) {
              startEventHandler(t0, event);
            }
          }