title: How to listen for user generated zoom in Google Maps?
body: <p>I want to know when a Google Maps zoom_changed event is fired specifically by a user interaction with the +/- zoom buttons.  If I use a general event listener for zoom_changed, I can't tell if it is a user-generated event or a zoom change caused by something like fitBounds().  Looking for the best way to do this.  </p>
  
  <p>I've tried the following things, none of which seem to work:</p>
  
  <p>1) Looked for event information on zoom_changed.  There appears to be none.</p>
  
  <p>2) Add listeners for mouseover and mouseout that let me set a flag to see if the user is in the map bounds, and check the flag on zoom_changed.  This doesn't work because the map does not consider the zoom buttons as part of the map frame (in other words, hovering over zoom buttons triggers the mouseout event).</p>
  
  <p>3) Add a normal (non-gMap) listener to the zoom buttons.  However, I can't find a definitive CSS selector that will allow me to grab just the buttons.</p>
  
  <p>4) Looked for a function in the gMaps API that would let me do something like getZoomElements(), and then I could set listeners using that. </p>
  
  <p>The weird thing is I can clearly do what I want if I add a custom control to the map.  It seems very odd that they would force me to do that instead of having a hook into the default zoom controls.</p>