diff --git a/builtin_function.go b/builtin_function.go
index 080b624..f244344 100644
--- a/builtin_function.go
+++ b/builtin_function.go
@@ -90,5 +90,5 @@ func builtinFunction_bind(call FunctionCall) Value {
 		this = toValue_object(call.runtime.GlobalObject)
 	}
 
-	return toValue_object(call.runtime.newBoundFunctionObject(targetObject, this, argumentList))
+	return toValue_object(call.runtime.newBoundFunction(targetObject, this, argumentList))
 }
diff --git a/function_test.go b/function_test.go
index 62313f9..0530a3d 100644
--- a/function_test.go
+++ b/function_test.go
@@ -135,8 +135,8 @@ func TestFunction_bind(t *testing.T) {
             return "abc";
         };
         def = abc.bind();
-        def();
-    `, "abc")
+        [ typeof def.prototype, typeof def.hasOwnProperty, def() ];
+    `, "object,function,abc")
 
 	test(`
         abc = function(){
@@ -146,4 +146,22 @@ func TestFunction_bind(t *testing.T) {
         ghi = abc.bind(undefined, "abc", "ghi");
         [ def(), def("def"), ghi("def") ];
     `, ",def,ghi")
+
+	test(`
+        var abc = function () {};
+        var ghi;
+        try {
+            Object.defineProperty(Function.prototype, "xyzzy", {
+                value: 1001,
+                writable: true,
+                enumerable: true,
+                configurable: true
+            });
+            var def = abc.bind({});
+            ghi = !def.hasOwnProperty("xyzzy") && ghi.xyzzy === 1001;
+        } finally {
+            delete Function.prototype.xyzzy;
+        }
+        [ ghi ];
+    `, "true")
 }
diff --git a/type_function.go b/type_function.go
index eee7cb7..4203551 100644
--- a/type_function.go
+++ b/type_function.go
@@ -43,6 +43,15 @@ func (runtime *_runtime) newBoundFunctionObject(target *_object, this Value, arg
 	return self
 }
 
+func (runtime *_runtime) newBoundFunction(target *_object, this Value, argumentList []Value) *_object {
+	self := runtime.newBoundFunctionObject(target, this, argumentList)
+	self.prototype = runtime.Global.FunctionPrototype
+	prototype := runtime.newObject()
+	self.defineProperty("prototype", toValue_object(prototype), 0100, false)
+	prototype.defineProperty("constructor", toValue_object(self), 0100, false)
+	return self
+}
+
 func (self *_object) functionValue() _functionObject {
 	value, _ := self.value.(_functionObject)
 	return value