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);
            }
          }
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);
            }
          }
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 ) ; } }
Callbacks  on touchstart
Callbacks on touchstart