title: Google Maps API v3: Is there a callback or event listener for a setMap() event?
body: <p>I am using Google Maps API v3 on a website I am developing. I have a drop-down box beneath my map which allows the user to switch between different sets of markers to be displayed on the map. Each marker is displayed using <code>marker.setMap()</code>.</p>
  
  <p>My problem is that the map sometimes takes a long time to display the new markers, especially in IE. I want to show a "Loading" animation while the map is switching markers. But I don't know how to detect when the map has finished displaying the new data (there is no page load, since this is all AJAX). Is there a callback or event listener for a <code>setMap()</code> event, so I can call a function to stop the "Loading" animation when the last marker has finished loading?</p>