diff -r d7cff2cba6e5 -r 6dc2c6c752df javaquery/api/src/main/java/org/apidesign/bck2brwsr/htmlpage/Knockout.java
--- a/javaquery/api/src/main/java/org/apidesign/bck2brwsr/htmlpage/Knockout.java	Thu Apr 18 20:09:45 2013 +0200
+++ b/javaquery/api/src/main/java/org/apidesign/bck2brwsr/htmlpage/Knockout.java	Thu Apr 18 23:09:30 2013 +0200
@@ -40,28 +40,6 @@
     static Knockout next;
     private final Object model;
 
-    static {
-        BufferedReader r = new BufferedReader(new InputStreamReader(Knockout.class.getResourceAsStream("knockout-2.2.1.js")));
-        StringBuilder sb = new StringBuilder();
-        for (;;) {
-            try {
-                String l = r.readLine();
-                if (l == null) {
-                    break;
-                }
-                sb.append(l).append('\n');
-            } catch (IOException ex) {
-                throw new IllegalStateException(ex);
-            }
-        }
-        web().executeScript(sb.toString());
-        Object ko = web().executeScript("ko");
-        assert ko != null : "Knockout library successfully defined 'ko'";
-        
-        Console.register(web());
-    }
-    
-    
     Knockout(Object model) {
         this.model = model == null ? this : model;
     }
@@ -70,43 +48,15 @@
         return model;
     }
 
-    private static final JSObject KObject;
-    static {
-        KObject = (JSObject) web().executeScript(
-            "(function(scope) {"
-            + "  var kCnt = 0; "
-            + "  scope.KObject = {};"
-            + "  scope.KObject.create= function(value) {"
-            + "    var cnt = ++kCnt;"
-            + "    var ret = {};"
-            + "    ret.toString = function() { return 'KObject' + cnt + ' value: ' + value + ' props: ' + Object.keys(this); };"
-            + "    return ret;"
-            + "  };"
-            
-            + "  scope.KObject.array= function() {"
-            + "    return Array.prototype.slice.call(arguments);"
-            + "  };"
-            
-            + "  scope.KObject.expose = function(bindings, model, prop, sig) {"
-            + "    bindings[prop] = function(data, ev) {"
-//            + "         console.log(\"  callback on prop: \" + prop);"
-            + "      model[sig](data, ev);"
-            + "    };"
-            + "  };"
-            
-            + "})(window); window.KObject"
-            );
-    }
-    
     static Object toArray(Object[] arr) {
-        return KObject.call("array", arr);
+        return InvokeJS.KObject.call("array", arr);
     }
     
     public static <M> Knockout applyBindings(
         Object model, String[] propsGettersAndSetters,
         String[] methodsAndSignatures
     ) {
-        Object bindings = KObject.call("create", model);
+        Object bindings = InvokeJS.KObject.call("create", model);
         applyImpl(propsGettersAndSetters, model.getClass(), bindings, model, methodsAndSignatures);
         return new Knockout(bindings);
     }
@@ -117,7 +67,7 @@
         Object bindings = next;
         next = null;
         if (bindings == null) {
-            bindings = KObject.call("create", model);
+            bindings = InvokeJS.KObject.call("create", model);
         }
         applyImpl(propsGettersAndSetters, modelClass, bindings, model, methodsAndSignatures);
         applyBindings(bindings);
@@ -167,6 +117,9 @@
         Object bindings, Object model, String prop, String getter, String setter, boolean primitive, boolean array
     ) {
         WebEngine e = web();
+        if (e == null) {
+            return;
+        }
         JSObject bnd = (JSObject) e.executeScript("var x = {}; x.bnd = "
         + "new Function('ko', 'bindings', 'model', 'prop', 'getter', 'setter', 'primitive', 'array', '"
         + "var bnd = {"
@@ -198,7 +151,7 @@
         + "};"
         + "bindings[prop] = ko.computed(bnd);'"
         + "); x;");
-        
+
         Object ko = e.executeScript("ko");
         try {
             KOProperty kop = new KOProperty(model, strip(getter), strip(setter));
@@ -224,9 +177,13 @@
     private static void expose(
         Object bindings, Object model, String prop, String sig
     ) {
+        WebEngine e = web();
+        if (e == null) {
+            return;
+        }
         try {
             KOFunction f = new KOFunction(model, strip(sig));
-            KObject.call("expose", bindings, f, prop, "call");
+            InvokeJS.KObject.call("expose", bindings, f, prop, "call");
         } catch (Throwable ex) {
             LOG.log(Level.SEVERE, "Cannot define binding for " + prop + " in model " + model, ex);
         }
@@ -234,8 +191,10 @@
     
     @JavaScriptBody(args = { "bindings" }, body = "ko.applyBindings(bindings);")
     private static void applyBindings(Object bindings) {
-        JSObject ko = (JSObject) web().executeScript("ko");
-        ko.call("applyBindings", bindings);
+        if (web() != null) {
+            JSObject ko = (JSObject) web().executeScript("ko");
+            ko.call("applyBindings", bindings);
+        }
     }
     
     private static WebEngine web() {
@@ -267,4 +226,50 @@
                 bindings, model, methodsAndSignatures[i], methodsAndSignatures[i + 1]);
         }
     }
+    
+    private static final class InvokeJS {
+        static final JSObject KObject;
+
+        static {
+            BufferedReader r = new BufferedReader(new InputStreamReader(Knockout.class.getResourceAsStream("knockout-2.2.1.js")));
+            StringBuilder sb = new StringBuilder();
+            for (;;) {
+                try {
+                    String l = r.readLine();
+                    if (l == null) {
+                        break;
+                    }
+                    sb.append(l).append('\n');
+                } catch (IOException ex) {
+                    throw new IllegalStateException(ex);
+                }
+            }
+            web().executeScript(sb.toString());
+            Object ko = web().executeScript("ko");
+            assert ko != null : "Knockout library successfully defined 'ko'";
+
+            Console.register(web());
+            KObject = (JSObject) web().executeScript(
+                "(function(scope) {"
+                + "  var kCnt = 0; "
+                + "  scope.KObject = {};"
+                + "  scope.KObject.create= function(value) {"
+                + "    var cnt = ++kCnt;"
+                + "    var ret = {};"
+                + "    ret.toString = function() { return 'KObject' + cnt + ' value: ' + value + ' props: ' + Object.keys(this); };"
+                + "    return ret;"
+                + "  };"
+                + "  scope.KObject.array= function() {"
+                + "    return Array.prototype.slice.call(arguments);"
+                + "  };"
+                + "  scope.KObject.expose = function(bindings, model, prop, sig) {"
+                + "    bindings[prop] = function(data, ev) {"
+                //            + "         console.log(\"  callback on prop: \" + prop);"
+                + "      model[sig](data, ev);"
+                + "    };"
+                + "  };"
+                + "})(window); window.KObject");
+        }
+        
+    }
 }