source/sortable-helper.js
function (event) {

          var touchInvalid = false;
          if (event.touches !== undefined && event.touches.length > 1) {
            touchInvalid = true;
          } else if (event.originalEvent !== undefined &&
            event.originalEvent.touches !== undefined && event.originalEvent.touches.length > 1) {
            touchInvalid = true;
          }
          return touchInvalid;
        }
function (event) {

          var touchInvalid = false;
          if (event.touches !== undefined && event.touches.length > 1) {
            touchInvalid = true;
          } else if (event.originalEvent !== undefined &&
            event.originalEvent.touches !== undefined && event.originalEvent.touches.length > 1) {
            touchInvalid = true;
          }
          return touchInvalid;
        }
function ( event ) { var touchInvalid = false ; if ( event . touches !== undefined && event . touches . length > 1 ) { touchInvalid = true ; } else if ( event . originalEvent !== undefined && event . originalEvent . touches !== undefined && event . originalEvent . touches . length > 1 ) { touchInvalid = true ; } return touchInvalid ; }
Checks whether the touch is valid and multiple.

@param event the event object.
@returns {boolean} true if touch is multiple.
Checks whether the touch is valid and multiple .