http://play.elevatorsaga.com/

{
    init: function(elevators, floors) {
        var elevator = elevators[0]; // Let's use the first elevator
        var up = [];
        var down = [];
        floors.forEach(function(floor) {
            floor.on("up_button_pressed", function() {
                up.push(floor.floorNum());
            });
            floor.on("down_button_pressed", function() {
                down.push(floor.floorNum());
            });
        });
        elevator.on("idle stopped_at_floor", function() {
            var floorNum = 0;
            if (elevator.getPressedFloors().length > 0) {
                if (elevator.goingUpIndicator()) {
                    floorNum = Math.max.apply(Math, elevator.getPressedFloors());
                }
                else {
                    floorNum = Math.min.apply(Math, elevator.getPressedFloors());
                }
            }
            else if (up.length > 0)
            {
                if (down.length > 0)
                {
                    if (elevator.currentFloor() >= floors.length / 2)
                    {
                        floorNum = Math.max.apply(Math, down);
                    }
                    else
                    {
                        floorNum = Math.min.apply(Math, up);
                    }
                }
                else
                {
                    floorNum = Math.min.apply(Math, up);
                }
            }
            else if (down.length > 0)
            {
                floorNum = Math.max.apply(Math, down);
            }
            elevator.goToFloor(floorNum);
            if (floorNum < elevator.currentFloor()) {
                elevator.goingUpIndicator(false);
                elevator.goingDownIndicator(true);
                if (down.indexOf(elevator.currentFloor()) != -1) {
                    down.splice(down.indexOf(elevator.currentFloor()), 1);
                }
            }
            else if (floorNum > elevator.currentFloor()) {
                elevator.goingUpIndicator(true);
                elevator.goingDownIndicator(false);
                if (up.indexOf(elevator.currentFloor()) != -1) {
                    up.splice(up.indexOf(elevator.currentFloor()), 1);
                }
            }
            else {
                elevator.goingUpIndicator(true);
                elevator.goingDownIndicator(true);
            }
        });
        elevator.on("floor_button_pressed", function(floorNum) {
            if (elevator.destinationQueue.length == 0) {
                elevator.goToFloor(floorNum);
                if (floorNum < elevator.currentFloor()) {
                    elevator.goingUpIndicator(false);
                    elevator.goingDownIndicator(true);
                    if (down.indexOf(elevator.currentFloor()) != -1) {
                        down.splice(down.indexOf(elevator.currentFloor()), 1);
                    }
                }
                else if (floorNum > elevator.currentFloor()) {
                    elevator.goingUpIndicator(true);
                    elevator.goingDownIndicator(false);
                    if (up.indexOf(elevator.currentFloor()) != -1) {
                        up.splice(up.indexOf(elevator.currentFloor()), 1);
                    }
                }
                else {
                    elevator.goingUpIndicator(true);
                    elevator.goingDownIndicator(true);
                }
            }
        });
        elevator.on("passing_floor", function(floorNum, direction) {
            var bShouldStop = false;
            if (elevator.getPressedFloors().indexOf(floorNum) != -1) {
                bShouldStop = true;
            } else if (elevator.loadFactor() < 0.6) {
                if (direction == "up" && up.indexOf(floorNum) != -1) {
                    bShouldStop = true;
                } else if (direction == "down" && down.indexOf(floorNum) != -1) {
                    bShouldStop = true;
                }
            }
            if (bShouldStop) {
                elevator.stop();
                elevator.goToFloor(floorNum);
            }
        });
    },
    update: function(dt, elevators, floors) {
        // We normally don't need to do anything here
    }
}