code: function eventTap ( event ) {
  
              // The tap event shouldn't propagate up
              event.stopPropagation();
  
              var proposal = calcPointToPercentage(event.calcPoint);
              var handleNumber = getClosestHandle(proposal);
  
              // Tackle the case that all handles are 'disabled'.
              if ( handleNumber === false ) {
                  return false;
              }
  
              // Flag the slider as it is now in a transitional state.
              // Transition takes a configurable amount of ms (default 300). Re-enable the slider after that.
              if ( !options.events.snap ) {
                  addClassFor(scope_Target, options.cssClasses.tap, options.animationDuration);
              }
  
              setHandle(handleNumber, proposal, true, true);
  
              setZindex();
  
              fireEvent('slide', handleNumber, true);
              fireEvent('set', handleNumber, true);
              fireEvent('change', handleNumber, true);
              fireEvent('update', handleNumber, true);
  
              if ( options.events.snap ) {
                  eventStart(event, { handleNumbers: [handleNumber] });
              }
          }
docs: Move closest handle to tapped location.