Question: I'm building a website with ASP.NET MVC where one feature displays some points on a Google map, using the Google Maps Javascript API. As I have a lot of points, I don't want to fetch them all; rather, I want to get only the ones that are in the current view area that the user is looking at on the map (the bounding box).

To do that, I will make an AJAX request to my C# code that returns all the points inside a certain bounding box. However, I need to somehow create an event handler that catches whenever the map is panned or zoomed by the user.

**How can I detect when a map using the Google Maps Javascript API is panned or zoomed and fire an event handler?** 

**UPDATE:** I know that I have to implement an event listener. Can someone point me towards a list of events that I can use for the Map object? `click` is one of those events, but what are the ones that relate to zooming and panning?

Answer: 
It looks like you're looking for the `idle` event:

> 
> This event is fired when the map becomes idle after panning or zooming.
> 
> 
> 

Example:

```
<!DOCTYPE html>
<html> 
<head> 
  <meta http-equiv="content-type" content="text/html; charset=UTF-8" /> 
  <title>Google Maps Events</title> 
  <script src="http://maps.google.com/maps/api/js?sensor=false" 
          type="text/javascript"></script>
</head> 
<body>
  <div id="map" style="width: 500px; height: 400px;"></div>

  <script type="text/javascript">
    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 10,
      center: new google.maps.LatLng(-33.92, 151.25),
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });

    google.maps.event.addListener(map, 'idle', function() {
      var bounds = map.getBounds();

      console.log('North East: ' +
                  bounds.getNorthEast().lat() + ' ' + 
                  bounds.getNorthEast().lng());

      console.log('South West: ' +
                  bounds.getSouthWest().lat() + ' ' + 
                  bounds.getSouthWest().lng());

      // Your AJAX code in here ...
    });
  </script>
</body>
</html>

```

In addition, you can find the list of all events exported by the `google.maps.Map` object from the API Reference:

* [Google Maps Javascript API V3 Reference: Map Class](http://code.google.com/apis/maps/documentation/javascript/reference.html#Map)
i think you need use an listener...
in this case an event listener..

[gmaps events reference](http://code.google.com/apis/maps/documentation/javascript/v2/events.html)

if you use v3 search on v3 reference for listeners