Multiple FeatureType in WFS Protocol

Question

I would like to pass multiple featureTypes to WFS protocol in order to accomplish a search feature in my app. the idea worked just fine with one featureType, but now I need to add another one to expand my search scope. Here is what I did:

var featureTypes = ["Layer_1", "Layer_2"]; 
var wfsProtocol = new OpenLayers.Protocol.WFS.v1_1_0({ 
 url: URL, 
 featureType: featureTypes,
 featureNS: "http://mapmap.org", 
 srsName: "EPSG:3857", 
 version: "1.1.0", 
 extractAttributes: true, 
 isBaseLayer: false, 
 visibility: true 
 });
wfsProtocol.read({ 
 filter: filter, 
 callback: processTheQuery, 
 scope: [new OpenLayers.Strategy.Fixed({preload: true})],
 })

But still didn't work, Any idea?

Answer 1

Found a solution!

just combining the two layers in one by UNION. It works for me.