Question

This is my code, I think it may has some mistakes:

        var bounds_array;
        google.maps.event.addListener(map,'bounds_changed', function (){
            var bounds_=map.getBounds();
            if(bounds_){
                var leftBottom=[bounds_.getSouthWest().lat(),bounds_.getSouthWest().lng()]
                var rightTop=[bounds_.getNorthEast().lat(),bounds_.getNorthEast().lng()]
                bounds_array=[leftBottom,rightTop];
            }
        });

    function check_is_in_or_out(marker){
        var leftBottom=bounds_array[0],rightTop=bounds_array[1];
        var marker_p=[marker.getPosition().lat(),marker.getPosition().lng()];
        if(marker_p[0]<leftBottom[0]||marker_p[0]>rightTop[0]||
            marker_p[1]<leftBottom[1]||marker_p[1]>rightTop[1])return 0;//0 is out
        else return 1;//1 is in
    }

Is this code enough to check the bounds is in or out?

Answer 1

The LatLngBounds object comes with a contains() method which takes a LatLng point and returns true if the point happens to be within the bounds, or false if outside.

Therefore, what about something like the following?

function check_is_in_or_out(marker){
  return map.getBounds().contains(marker.getPosition());
}