allow for setting opacity of alpha image divs. also give both Icon and Marker setOpacity() functions. added tests and modified examples/markers.html to show how to do it.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@1541 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

tests/test_Marker.html

@@ -45,6 +45,32 @@
         
     }
 
+    function test_02_Marker_setOpacity(t) {
+        t.plan( 2 );
+        
+        var map = new OpenLayers.Map("map");
+
+        var url = "http://octo.metacarta.com/cgi-bin/mapserv";
+        layer = new OpenLayers.Layer.WMS(name, url);
+
+        map.addLayer(layer);
+        
+        mlayer = new OpenLayers.Layer.Markers('Test Layer');
+        map.addLayer(mlayer);
+               
+        map.zoomToExtent(new OpenLayers.Bounds(-50,-50,50,50));
+
+        //onscreen marker
+        var ll = new OpenLayers.LonLat(0,0);
+        var marker = new OpenLayers.Marker(ll);
+        mlayer.addMarker(marker);
+
+        t.ok(!marker.icon.imageDiv.style.opacity, "default marker has no opacity");
+        
+        marker.setOpacity(0.5);
+
+        t.eq(marker.icon.imageDiv.style.opacity + "", "0.5", "marker.setOpacity() works");
+    }
 
   // -->
   </script>