diff --git a/Lib/javascript/v8/javascriptcode.swg b/Lib/javascript/v8/javascriptcode.swg
index 070ef2e2d..527efe115 100644
--- a/Lib/javascript/v8/javascriptcode.swg
+++ b/Lib/javascript/v8/javascriptcode.swg
@@ -55,16 +55,30 @@ fail:
   return scope.Close(v8::Undefined());
 }%}
 
-/*
-%fragment ("JS_mainctordefn", "templates")
-%{
-  // TODO: implement JS_mainctordefn
+%fragment ("JS_mainctordefn", "templates") %{
+v8::Handle<v8::Value> $jswrapper(const v8::Arguments& args) {
+  v8::HandleScope scope;
+  
+  v8::TryCatch tryCatch;
+  // switch all cases by means of series of if-returns. 
+  $jsdispatchcases
+
+  // default:
+  if(!tryCatch.HasCaught())
+    SWIG_exception_fail(SWIG_ERROR, "Illegal arguments for contruction of $jsmangledname");
+  
+fail:
+  scope.Close(v8::Undefined());
+}
 %}
-*/
 
 %fragment ("JS_ctor_dispatch_case", "templates")
-%{
-  // TODO: implement JS_ctor_dispatch_case
+%{if(args.Length() == $jsargcount) {
+    v8::Handle<v8::Value> self = $jswrapper(args);
+    if(!self->IsUndefined()) { 
+      tryCatch.Reset(); return scope.Close(self); /* reset exception and return */
+    }
+  }
 %}
 
 %fragment ("JS_destructordefn", "templates")
diff --git a/Source/Modules/javascript.cxx b/Source/Modules/javascript.cxx
index e7fa8801a..a6261394f 100644
--- a/Source/Modules/javascript.cxx
+++ b/Source/Modules/javascript.cxx
@@ -837,6 +837,7 @@ int JSEmitter::emitCtor(Node *n) {
       String *wrap_name = Swig_name_wrapper(Getattr(n, "sym:name"));
       Template t_mainctor(getTemplate("JS_mainctordefn"));
       t_mainctor.replace(T_WRAPPER, wrap_name)
+          .replace(T_NAME_MANGLED, state.clazz(NAME_MANGLED))
           .replace(T_DISPATCH_CASES, state.clazz(CTOR_DISPATCHERS))
           .pretty_print(f_wrappers);
       state.clazz(CTOR, wrap_name);
@@ -1845,7 +1846,7 @@ void V8Emitter::marshalInputArgs(Node *n, ParmList *parms, Wrapper *wrapper, Mar
   }
 
   // store number of arguments for argument checks
-  int num_args = emit_num_arguments(parms) - startIdx;
+  int num_args = emit_num_arguments(parms);
   String *argcount = NewString("");
   Printf(argcount, "%d", num_args);
   Setattr(n, ARGCOUNT, argcount);