Time for Action – using the allOverlays Map property

Let's take a look at using the allOverlays property and not specifying a div when creating a map.

1. In your init() function, let's create our map object with allOverlays set to true and with some controls passed in. We will also not specify an HTML element:

   var map = new OpenLayers.Map({
     allOverlays: true,
     controls: [new OpenLayers.Control.Navigation(),new OpenLayers.Control.PanZoom(),new OpenLayers.Control.LayerSwitcher()]
   });

2. Now, let's create a couple of layers so we can see how the allOverlays property works. We'll assume that you will add WMS layers to your maps for future examples.

           var wms_layer_all = new OpenLayers.Layer.WMS( 
               'OpenLayers WMS', 
               'http://vmap0.tiles.osgeo.org/wms/vmap0', 
               {layers: 'basic'}, 
               {} 
           ); 
           
           var wms_layer_labels = new OpenLayers.Layer.WMS( 
               'Labels', 
               'http://vmap0.tiles.osgeo.org/wms/vmap0', 
           ...