diff --git a/platform/firefox/frameModule.js b/platform/firefox/frameModule.js
new file mode 100644
index 0000000..7465c2b
--- /dev/null
+++ b/platform/firefox/frameModule.js
@@ -0,0 +1,169 @@
+/* global Services, Components, XPCOMUtils */
+/* exported EXPORTED_SYMBOLS, isTabbed */
+
+'use strict';
+
+var EXPORTED_SYMBOLS = ['contentPolicy', 'docObserver'];
+
+Components.utils['import']('resource://gre/modules/Services.jsm');
+Components.utils['import']('resource://gre/modules/XPCOMUtils.jsm');
+
+const Ci = Components.interfaces, appName = 'ublock';
+
+let getMessager = function(win) {
+    try {
+        // e10s
+        return win
+            .QueryInterface(Ci.nsIInterfaceRequestor)
+            .getInterface(Ci.nsIWebNavigation)
+            .QueryInterface(Ci.nsIDocShellTreeItem)
+            .rootTreeItem
+            .QueryInterface(Ci.nsIInterfaceRequestor)
+            .getInterface(Ci.nsIContentFrameMessageManager);
+    } catch (ex) {
+        return win
+            .QueryInterface(Ci.nsIInterfaceRequestor)
+            .getInterface(Ci.nsIWebNavigation)
+            .QueryInterface(Ci.nsIDocShell)
+            .QueryInterface(Ci.nsIInterfaceRequestor)
+            .getInterface(Ci.nsIContentFrameMessageManager);
+    }
+};
+
+let contentPolicy = {
+    classDescription: 'ContentPolicy implementation',
+    classID: Components.ID('{e6d173c8-8dbf-4189-a6fd-189e8acffd27}'),
+    contractID: '@ublock/content-policy;1',
+    ACCEPT: Ci.nsIContentPolicy.ACCEPT,
+    REJECT: Ci.nsIContentPolicy.REJECT_REQUEST,
+    get componentRegistrar() {
+        return Components.manager.QueryInterface(Ci.nsIComponentRegistrar);
+    },
+    get categoryManager() {
+        return Components.classes['@mozilla.org/categorymanager;1']
+                .getService(Ci.nsICategoryManager);
+    },
+    QueryInterface: XPCOMUtils.generateQI([
+        Ci.nsIFactory,
+        Ci.nsIContentPolicy,
+        Ci.nsISupportsWeakReference
+    ]),
+    createInstance: function(outer, iid) {
+        if (outer) {
+            throw Components.results.NS_ERROR_NO_AGGREGATION;
+        }
+
+        return this.QueryInterface(iid);
+    },
+    register: function() {
+        this.componentRegistrar.registerFactory(
+            this.classID,
+            this.classDescription,
+            this.contractID,
+            this
+        );
+        this.categoryManager.addCategoryEntry(
+            'content-policy',
+            this.contractID,
+            this.contractID,
+            false,
+            true
+        );
+    },
+    unregister: function() {
+        this.componentRegistrar.unregisterFactory(this.classID, this);
+        this.categoryManager.deleteCategoryEntry(
+            'content-policy',
+            this.contractID,
+            false
+        );
+    },
+    shouldLoad: function(type, location, origin, context) {
+        if (type === 6 || !context || !/^https?$/.test(location.scheme)) {
+            return this.ACCEPT;
+        }
+
+        let win = (context.ownerDocument || context).defaultView;
+
+        if (!win) {
+            return this.ACCEPT;
+        }
+
+        let result = getMessager(win).sendSyncMessage('ublock:onBeforeRequest', {
+            url: location.spec,
+            type: type,
+            tabId: -1,
+            frameId: win === win.top ? 0 : 1,
+            parentFrameId: win === win.top ? -1 : 0
+        })[0];
+
+        return result === true ? this.REJECT : this.ACCEPT;
+    }/*,
+    shouldProcess: function() {
+        return this.ACCEPT;
+    }*/
+};
+
+let docObserver = {
+    contentBaseURI: 'chrome://ublock/content/js/',
+    initContext: function(win, sandbox) {
+        let messager = getMessager(win);
+
+        if (sandbox) {
+            win = Components.utils.Sandbox([win], {
+                sandboxPrototype: win,
+                wantComponents: false,
+                wantXHRConstructor: false
+            });
+        }
+
+        win.sendAsyncMessage = messager.sendAsyncMessage;
+        win.addMessageListener = messager.ublock_addMessageListener;
+        win.removeMessageListener = messager.ublock_removeMessageListener;
+
+        return win;
+    },
+    register: function() {
+        Services.obs.addObserver(this, 'document-element-inserted', false);
+    },
+    unregister: function() {
+        Services.obs.removeObserver(this, 'document-element-inserted');
+    },
+    observe: function(doc) {
+        let win = doc.defaultView;
+
+        if (!win) {
+            return;
+        }
+
+        if (!/^https?:$/.test(win.location.protocol)) {
+            if (win.location.protocol === 'chrome:'
+                && win.location.host === appName) {
+                this.initContext(win);
+            }
+
+            return;
+        }
+
+        let lss = Services.scriptloader.loadSubScript;
+        win = this.initContext(win, true);
+
+        lss(this.contentBaseURI + 'vapi-client.js', win);
+        lss(this.contentBaseURI + 'contentscript-start.js', win);
+
+        if (doc.readyState === 'interactive' || doc.readyState === 'complete') {
+            lss(this.contentBaseURI + 'contentscript-end.js', win);
+        }
+        else {
+            let docReady = function(e) {
+                this.removeEventListener(e.type, docReady, true);
+                lss(docObserver.contentBaseURI + 'contentscript-end.js', win);
+            };
+
+            doc.addEventListener('DOMContentLoaded', docReady, true);
+        }
+    }
+};
+
+contentPolicy.register();
+docObserver.register();