Google Maps API 3 - limit pan/map bounds

You have your strictBounds mixed up - change the order of them and it should work fine.

A LatLngBounds should be SW corner first, NE corner second: http://code.google.com/apis/maps/documentation/javascript/reference.html#LatLngBounds

var strictBounds = new google.maps.LatLngBounds(
  new google.maps.LatLng(49.90878, -7.69042),
  new google.maps.LatLng(60.88770, -0.83496) 
);

Just for anyone who stumbles upon the now-outdated info on this page as I did, the maps API now provides a built-in way to restrict the map viewport bounds via the restriction property of the MapOptions interface, see docs here. This example restricts north-south panning from showing Antarctica:

function initMap() {
    map = new google.maps.Map(document.getElementById('map'), {
      center: {lat: 20, lng: -52},
      zoom: 3,        
      restriction: {latLngBounds:{north: 83.8, south: -57, west: -180, east: 180}}
    }); 
}

Above code helped me, but didn't solve my issue. I needed to disable the panning based on polygon drawn on the map. I needed to limit panning to that particular window of the map. So user not pan faraway from the initial map.

function disablePanning(enableBounds) {
// listen to bound change event once to store the SW and NE corner

google.maps.event.addListener(map, 'bounds_changed', function() {
    // only set it once
    if (enableBounds == null) {
        enableBounds = map.getBounds();
    }
});
var lastValidCenter=null;
google.maps.event.clearListeners(map,'center_changed');
google.maps.event.addListener(map, 'center_changed', function() {
    if(enableBounds!=null && lastValidCenter==null){
        lastValidCenter = enableBounds.getCenter();
    }
    if (enableBounds != null && enableBounds != 'undefined') {
        var ne = enableBounds.getNorthEast();
        var sw = enableBounds.getSouthWest();
        var allowedBounds = new google.maps.LatLngBounds(
                new google.maps.LatLng(sw.lat(), sw.lng()),
                new google.maps.LatLng(ne.lat(), ne.lng()));

        if (allowedBounds.contains(map.getCenter())) {
            // still within valid bounds, so save the last valid position
            lastValidCenter = enableBounds.getCenter();
            return;
        }

        // not valid anymore => return to last valid position
        if(lastValidCenter!=null)
            map.panTo(lastValidCenter);
    }
});

}