diff --git a/CHANGES.current b/CHANGES.current
index 5872d6161..d925e5ffc 100644
--- a/CHANGES.current
+++ b/CHANGES.current
@@ -5,6 +5,10 @@ See the RELEASENOTES file for a summary of changes in each release.
 Version 3.0.9 (in progress)
 ===========================
 
+2016-01-12: olly
+	    [Javascript] For v8 >= 4.3.0, use V8_MAJOR_VERSION.
+	    Fixes https://github.com/swig/swig/issues/561.
+
 2016-01-10: ahnolds
             Improved size_t and ptrdiff_t typemaps to support large values
             on platforms where sizeof(size_t) > sizeof(unsigned long) and
diff --git a/Doc/Manual/Javascript.html b/Doc/Manual/Javascript.html
index 56f83b763..405583b4f 100644
--- a/Doc/Manual/Javascript.html
+++ b/Doc/Manual/Javascript.html
@@ -90,11 +90,22 @@ $ swig -javascript -jsc example.i</pre>
 $ swig -c++ -javascript -jsc example.i</pre>
 </div>
 <p>The V8 code that SWIG generates should work with most versions from 3.11.10 up to 3.29.14 and later.</p>
-<p>Specify the V8 version when running SWIG (e.g. 3.25.30)</p>
+<p>The API headers for V8 &gt;= 4.3.0 define constants which SWIG can use to
+determine the V8 version it is compiling for.  For versions &lt; 4.3.0, you
+need to specify the V8 version when running SWIG.  This is specified as a hex
+constant, but the constant is read as pairs of decimal digits, so for V8
+3.25.30 use constant 0x032530.  This scheme can't represent components &gt; 99,
+but this constant is only useful for V8 &lt; 4.3.0, and no V8 versions from
+that era had a component &gt; 99.  For example:</p>
 <div class="shell">
 <pre>
 $ swig -c++ -javascript -v8 -DV8_VERSION=0x032530 example.i</pre>
 </div>
+<p>If you're targetting V8 &gt;= 4.3.0, you would just run swig like so:<p>
+<div class="shell">
+<pre>
+$ swig -c++ -javascript -v8 example.i</pre>
+</div>
 <p>This creates a C/C++ source file <code>example_wrap.c</code> or <code>example_wrap.cxx</code>. The generated C source file contains the low-level wrappers that need to be compiled and linked with the rest of your C/C++ application to create an extension module.</p>
 <p>The name of the wrapper file is derived from the name of the input file. For example, if the input file is <code>example.i</code>, the name of the wrapper file is <code>example_wrap.c</code>. To change this, you can use the -o option. The wrapped module will export one function which must be called to register the module with the Javascript interpreter. For example, if your module is named <code>example</code> the corresponding initializer for JavascriptCore would be</p>
 <div class="code">
diff --git a/Lib/javascript/v8/javascriptcode.swg b/Lib/javascript/v8/javascriptcode.swg
index 12db9b4ab..0bcb508f3 100644
--- a/Lib/javascript/v8/javascriptcode.swg
+++ b/Lib/javascript/v8/javascriptcode.swg
@@ -102,7 +102,7 @@ fail:
 %{
   if(args.Length() == $jsargcount) {
     errorHandler.err.Clear();
-#if (SWIG_V8_VERSION < 0x031903)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
     self = $jswrapper(args, errorHandler);
     if(errorHandler.err.IsEmpty()) {
       SWIGV8_ESCAPE(self);
@@ -124,13 +124,13 @@ fail:
 %fragment ("js_dtor", "templates")
 %{
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
 static void $jswrapper(v8::Persistent< v8::Value > object, void *parameter) {
   SWIGV8_Proxy *proxy = static_cast<SWIGV8_Proxy *>(parameter);
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
 static void $jswrapper(v8::Isolate *isolate, v8::Persistent<v8::Value> object, void *parameter) {
   SWIGV8_Proxy *proxy = static_cast<SWIGV8_Proxy *>(parameter);
-#elif (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
 static void $jswrapper(v8::Isolate *isolate, v8::Persistent<v8::Object> *object, SWIGV8_Proxy *proxy) {
 #else
 static void $jswrapper(const v8::WeakCallbackData<v8::Object, SWIGV8_Proxy> &data) {
@@ -148,11 +148,11 @@ static void $jswrapper(const v8::WeakCallbackData<v8::Object, SWIGV8_Proxy> &dat
 
   object.Clear();
   
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
   object.Dispose();
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
   object.Dispose(isolate);
-#elif (SWIG_V8_VERSION < 0x032100)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032100)
   object->Dispose(isolate);
 #else
   object->Dispose();
@@ -168,13 +168,13 @@ static void $jswrapper(const v8::WeakCallbackData<v8::Object, SWIGV8_Proxy> &dat
  * ----------------------------------------------------------------------------- */
 %fragment ("js_dtoroverride", "templates")
 %{
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
 static void $jswrapper(v8::Persistent<v8::Value> object, void *parameter) {
   SWIGV8_Proxy *proxy = static_cast<SWIGV8_Proxy *>(parameter);
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
 static void $jswrapper(v8::Isolate *isolate, v8::Persistent<v8::Value> object, void *parameter) {
   SWIGV8_Proxy *proxy = static_cast<SWIGV8_Proxy *>(parameter);
-#elif (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
 static void $jswrapper(v8::Isolate *isolate, v8::Persistent< v8::Object> *object, SWIGV8_Proxy *proxy) {
 #else
 static void $jswrapper(const v8::WeakCallbackData<v8::Object, SWIGV8_Proxy> &data) {
@@ -188,13 +188,13 @@ static void $jswrapper(const v8::WeakCallbackData<v8::Object, SWIGV8_Proxy> &dat
   }
   delete proxy;
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
   object.Dispose();
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
   object.Dispose(isolate);
-#elif (SWIG_V8_VERSION < 0x032100)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032100)
   object->Dispose(isolate);
-#elif (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
   object->Dispose();
 #else
   object.Clear();
@@ -326,7 +326,7 @@ fail:
 
   if(args.Length() == $jsargcount) {
     errorHandler.err.Clear();
-#if (SWIG_V8_VERSION < 0x031903)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
     jsresult = $jswrapper(args, errorHandler);
     if(errorHandler.err.IsEmpty()) {
       SWIGV8_ESCAPE(jsresult);
@@ -376,7 +376,7 @@ fail:
 %{
   if (SWIGTYPE_p$jsbaseclass->clientdata && !(static_cast<SWIGV8_ClientData *>(SWIGTYPE_p$jsbaseclass->clientdata)->class_templ.IsEmpty()))
   {
-#if (SWIG_V8_VERSION < 0x031903)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
     $jsmangledname_class->Inherit(static_cast<SWIGV8_ClientData *>(SWIGTYPE_p$jsbaseclass->clientdata)->class_templ);
 #else
     $jsmangledname_class->Inherit(
diff --git a/Lib/javascript/v8/javascripthelpers.swg b/Lib/javascript/v8/javascripthelpers.swg
index 969225401..f9901fb02 100644
--- a/Lib/javascript/v8/javascripthelpers.swg
+++ b/Lib/javascript/v8/javascripthelpers.swg
@@ -1,7 +1,7 @@
 %insert(runtime) %{
 
 // Note: since 3.19 there are new CallBack types, since 03.21.9 the old ones have been removed
-#if (SWIG_V8_VERSION < 0x031903)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
 typedef v8::InvocationCallback  SwigV8FunctionCallback;
 typedef v8::AccessorGetter      SwigV8AccessorGetterCallback;
 typedef v8::AccessorSetter      SwigV8AccessorSetterCallback;
diff --git a/Lib/javascript/v8/javascriptrun.swg b/Lib/javascript/v8/javascriptrun.swg
index dc4d37a48..57c5afcd6 100644
--- a/Lib/javascript/v8/javascriptrun.swg
+++ b/Lib/javascript/v8/javascriptrun.swg
@@ -7,13 +7,13 @@
 
 #define SWIGV8_SETWEAK_VERSION 0x032224
 
-#if (SWIG_V8_VERSION < 0x031803)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031803)
 #define SWIGV8_STRING_NEW2(cstr, len) v8::String::New(cstr, len)
 #else
 #define SWIGV8_STRING_NEW2(cstr, len) v8::String::NewFromUtf8(v8::Isolate::GetCurrent(), cstr, v8::String::kNormalString, len)
 #endif
 
-#if (SWIG_V8_VERSION < 0x031903)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
 typedef v8::Handle<v8::Value> SwigV8ReturnValue;
 typedef v8::Arguments SwigV8Arguments;
 typedef v8::AccessorInfo SwigV8PropertyCallbackInfo;
@@ -27,11 +27,11 @@ typedef v8::PropertyCallbackInfo<v8::Value> SwigV8PropertyCallbackInfo;
 #define SWIGV8_RETURN_INFO(val, info) info.GetReturnValue().Set(val); return
 #endif
 
-#if (SWIG_V8_VERSION < 0x032117)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032117)
 #define SWIGV8_HANDLESCOPE() v8::HandleScope scope
 #define SWIGV8_HANDLESCOPE_ESC() v8::HandleScope scope
 #define SWIGV8_ESCAPE(val) return scope.Close(val)
-#elif (SWIG_V8_VERSION < 0x032224)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032224)
 #define SWIGV8_HANDLESCOPE() v8::HandleScope scope(v8::Isolate::GetCurrent());
 #define SWIGV8_HANDLESCOPE_ESC() v8::HandleScope scope(v8::Isolate::GetCurrent());
 #define SWIGV8_ESCAPE(val) return scope.Close(val)
@@ -41,7 +41,7 @@ typedef v8::PropertyCallbackInfo<v8::Value> SwigV8PropertyCallbackInfo;
 #define SWIGV8_ESCAPE(val) return scope.Escape(val)
 #endif
 
-#if (SWIG_V8_VERSION < 0x032224)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032224)
 #define SWIGV8_ADJUST_MEMORY(size) v8::V8::AdjustAmountOfExternalAllocatedMemory(size)
 #define SWIGV8_CURRENT_CONTEXT() v8::Context::GetCurrent()
 #define SWIGV8_THROW_EXCEPTION(err) v8::ThrowException(err)
@@ -55,7 +55,7 @@ typedef v8::PropertyCallbackInfo<v8::Value> SwigV8PropertyCallbackInfo;
 #define SWIGV8_SYMBOL_NEW(sym) v8::String::NewFromUtf8(v8::Isolate::GetCurrent(), sym)
 #endif
 
-#if (SWIG_V8_VERSION < 0x032318)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032318)
 #define SWIGV8_ARRAY_NEW() v8::Array::New()
 #define SWIGV8_BOOLEAN_NEW(bool) v8::Boolean::New(bool)
 #define SWIGV8_EXTERNAL_NEW(val) v8::External::New(val)
@@ -83,9 +83,9 @@ typedef v8::PropertyCallbackInfo<v8::Value> SwigV8PropertyCallbackInfo;
 #define SWIGV8_NULL() v8::Null(v8::Isolate::GetCurrent())
 #endif
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
 #define SWIGV8_SET_CLASS_TEMPL(class_templ, class) class_templ = v8::Persistent<v8::FunctionTemplate>::New(class);
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
 #define SWIGV8_SET_CLASS_TEMPL(class_templ, class) class_templ = v8::Persistent<v8::FunctionTemplate>::New(v8::Isolate::GetCurrent(), class);
 #else
 #define SWIGV8_SET_CLASS_TEMPL(class_templ, class) class_templ.Reset(v8::Isolate::GetCurrent(), class);
@@ -156,13 +156,13 @@ public:
   };
 
   ~SWIGV8_Proxy() {
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
     handle.ClearWeak();
     handle.Dispose();
-#elif (SWIG_V8_VERSION < 0x032100)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032100)
     handle.ClearWeak(v8::Isolate::GetCurrent());
     handle.Dispose(v8::Isolate::GetCurrent());
-#elif (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
     handle.ClearWeak();
     handle.Dispose();
 #else    
@@ -170,7 +170,7 @@ public:
     handle.Reset();
 #endif
 
-#if (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
     handle.Clear();
 #endif
 
@@ -187,11 +187,11 @@ class SWIGV8_ClientData {
 public:
   v8::Persistent<v8::FunctionTemplate> class_templ;
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
   void (*dtor) (v8::Persistent< v8::Value> object, void *parameter);
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
   void (*dtor) (v8::Isolate *isolate, v8::Persistent< v8::Value> object, void *parameter);
-#elif (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
   void (*dtor) (v8::Isolate *isolate, v8::Persistent< v8::Object > *object, SWIGV8_Proxy *proxy);
 #else
   void (*dtor) (const v8::WeakCallbackData<v8::Object, SWIGV8_Proxy> &data);
@@ -205,7 +205,7 @@ SWIGRUNTIME int SWIG_V8_ConvertInstancePtr(v8::Handle<v8::Object> objRef, void *
 
   if(objRef->InternalFieldCount() < 1) return SWIG_ERROR;
 
-#if (SWIG_V8_VERSION < 0x031511)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031511)
   v8::Handle<v8::Value> cdataRef = objRef->GetInternalField(0);
   SWIGV8_Proxy *cdata = static_cast<SWIGV8_Proxy *>(v8::External::Unwrap(cdataRef));
 #else
@@ -233,13 +233,13 @@ SWIGRUNTIME int SWIG_V8_ConvertInstancePtr(v8::Handle<v8::Object> objRef, void *
 }
 
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
 SWIGRUNTIME void SWIGV8_Proxy_DefaultDtor(v8::Persistent< v8::Value > object, void *parameter) {
   SWIGV8_Proxy *proxy = static_cast<SWIGV8_Proxy *>(parameter);
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
 SWIGRUNTIME void SWIGV8_Proxy_DefaultDtor(v8::Isolate *, v8::Persistent< v8::Value > object, void *parameter) {
   SWIGV8_Proxy *proxy = static_cast<SWIGV8_Proxy *>(parameter);
-#elif (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
 SWIGRUNTIME void SWIGV8_Proxy_DefaultDtor(v8::Isolate *, v8::Persistent< v8::Object > *object, SWIGV8_Proxy *proxy) {
 #else
 SWIGRUNTIME void SWIGV8_Proxy_DefaultDtor(const v8::WeakCallbackData<v8::Object, SWIGV8_Proxy> &data) {
@@ -257,7 +257,7 @@ SWIGRUNTIME int SWIG_V8_GetInstancePtr(v8::Handle<v8::Value> valRef, void **ptr)
 
   if(objRef->InternalFieldCount() < 1) return SWIG_ERROR;
 
-#if (SWIG_V8_VERSION < 0x031511)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031511)
   v8::Handle<v8::Value> cdataRef = objRef->GetInternalField(0);
   SWIGV8_Proxy *cdata = static_cast<SWIGV8_Proxy *>(v8::External::Unwrap(cdataRef));
 #else
@@ -279,34 +279,34 @@ SWIGRUNTIME void SWIGV8_SetPrivateData(v8::Handle<v8::Object> obj, void *ptr, sw
   cdata->swigCMemOwn = (flags & SWIG_POINTER_OWN) ? 1 : 0;
   cdata->info = info;
 
-#if (SWIG_V8_VERSION < 0x031511)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031511)
   obj->SetPointerInInternalField(0, cdata);
 #else
   obj->SetAlignedPointerInInternalField(0, cdata);
 #endif
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
   cdata->handle = v8::Persistent<v8::Object>::New(obj);
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
   cdata->handle = v8::Persistent<v8::Object>::New(v8::Isolate::GetCurrent(), obj);
 #else
   cdata->handle.Reset(v8::Isolate::GetCurrent(), obj);
 #endif
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
   // clientdata must be set for owned data as we need to register the dtor
   if(cdata->swigCMemOwn && (SWIGV8_ClientData*)info->clientdata) {
     cdata->handle.MakeWeak(cdata, ((SWIGV8_ClientData*)info->clientdata)->dtor);
   } else {
     cdata->handle.MakeWeak(cdata, SWIGV8_Proxy_DefaultDtor);
   }
-#elif (SWIG_V8_VERSION < 0x031918)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031918)
   if(cdata->swigCMemOwn && (SWIGV8_ClientData*)info->clientdata) {
     cdata->handle.MakeWeak(v8::Isolate::GetCurrent(), cdata, ((SWIGV8_ClientData*)info->clientdata)->dtor);
   } else {
     cdata->handle.MakeWeak(v8::Isolate::GetCurrent(), cdata, SWIGV8_Proxy_DefaultDtor);
   }
-#elif (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
   if(cdata->swigCMemOwn && (SWIGV8_ClientData*)info->clientdata) {
     cdata->handle.MakeWeak(cdata, ((SWIGV8_ClientData*)info->clientdata)->dtor);
   } else {
@@ -320,9 +320,9 @@ SWIGRUNTIME void SWIGV8_SetPrivateData(v8::Handle<v8::Object> obj, void *ptr, sw
   }
 #endif
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
   cdata->handle.MarkIndependent();
-#elif (SWIG_V8_VERSION < 0x032100)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032100)
   cdata->handle.MarkIndependent(v8::Isolate::GetCurrent());
 #else
   cdata->handle.MarkIndependent();
@@ -351,15 +351,15 @@ SWIGRUNTIME v8::Handle<v8::Value> SWIG_V8_NewPointerObj(void *ptr, swig_type_inf
   v8::Handle<v8::FunctionTemplate> class_templ;
 
   if (ptr == NULL) {
-#if (SWIG_V8_VERSION < 0x031903)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
     SWIGV8_ESCAPE(SWIGV8_NULL());
 #else    
     v8::Local<v8::Primitive> result = SWIGV8_NULL();
     SWIGV8_ESCAPE(result);
-#endif    
+#endif
   }
 
-#if (SWIG_V8_VERSION < 0x031903)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
   if(info->clientdata != 0) {
     class_templ = ((SWIGV8_ClientData*) info->clientdata)->class_templ;
   } else {
@@ -483,7 +483,7 @@ swig_type_info *SwigV8Packed_UnpackData(v8::Handle<v8::Value> valRef, void *ptr,
 
     v8::Handle<v8::Object> objRef = valRef->ToObject();
 
-#if (SWIG_V8_VERSION < 0x031511)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031511)
     v8::Handle<v8::Value> cdataRef = objRef->GetInternalField(0);
     sobj = static_cast<SwigV8PackedData*>(v8::External::Unwrap(cdataRef));
 #else
@@ -511,13 +511,13 @@ int SWIGV8_ConvertPacked(v8::Handle<v8::Value> valRef, void *ptr, size_t sz, swi
   return SWIG_OK;
 }
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
 SWIGRUNTIME void _wrap_SwigV8PackedData_delete(v8::Persistent< v8::Value > object, void *parameter) {
   SwigV8PackedData *cdata = static_cast<SwigV8PackedData *>(parameter);
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
 SWIGRUNTIME void _wrap_SwigV8PackedData_delete(v8::Isolate *isolate, v8::Persistent<v8::Value> object, void *parameter) {
   SwigV8PackedData *cdata = static_cast<SwigV8PackedData *>(parameter);
-#elif (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
 SWIGRUNTIME void _wrap_SwigV8PackedData_delete(v8::Isolate *isolate, v8::Persistent<v8::Object> *object, SwigV8PackedData *cdata) {
 #else
 SWIGRUNTIME void _wrap_SwigV8PackedData_delete(const v8::WeakCallbackData<v8::Object, SwigV8PackedData> &data) {
@@ -527,15 +527,15 @@ SWIGRUNTIME void _wrap_SwigV8PackedData_delete(const v8::WeakCallbackData<v8::Ob
 
   delete cdata;
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
   object.Clear();
   object.Dispose();
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
   object.Clear();
   object.Dispose(isolate);
-#elif (SWIG_V8_VERSION < 0x032100)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032100)
   object->Dispose(isolate);
-#elif (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
   object->Dispose();
 #else
   object.Clear();
@@ -552,35 +552,35 @@ v8::Handle<v8::Value> SWIGV8_NewPackedObj(void *data, size_t size, swig_type_inf
 
   obj->SetHiddenValue(SWIGV8_STRING_NEW("__swig__packed_data__"), SWIGV8_BOOLEAN_NEW(true));
 
-#if (SWIG_V8_VERSION < 0x031511)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031511)
   obj->SetPointerInInternalField(0, cdata);
 #else
   obj->SetAlignedPointerInInternalField(0, cdata);
 #endif
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
   cdata->handle = v8::Persistent<v8::Object>::New(obj);
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
   cdata->handle = v8::Persistent<v8::Object>::New(v8::Isolate::GetCurrent(), obj);
 #else
   cdata->handle.Reset(v8::Isolate::GetCurrent(), obj);
 #endif
 
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
   cdata->handle.MakeWeak(cdata, _wrap_SwigV8PackedData_delete);
-#elif (SWIG_V8_VERSION < 0x031918)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031918)
   cdata->handle.MakeWeak(v8::Isolate::GetCurrent(), cdata, _wrap_SwigV8PackedData_delete);
-#elif (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < SWIGV8_SETWEAK_VERSION)
   cdata->handle.MakeWeak(cdata, _wrap_SwigV8PackedData_delete);
 #else
   cdata->handle.SetWeak(cdata, _wrap_SwigV8PackedData_delete);
 //  v8::V8::SetWeak(&cdata->handle, cdata, _wrap_SwigV8PackedData_delete);
 #endif
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
   cdata->handle.MarkIndependent();
-#elif (SWIG_V8_VERSION < 0x032100)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032100)
   cdata->handle.MarkIndependent(v8::Isolate::GetCurrent());
 #else
   cdata->handle.MarkIndependent();
@@ -600,7 +600,7 @@ v8::Handle<v8::Value> SWIGV8_NewPackedObj(void *data, size_t size, swig_type_inf
 
 SWIGRUNTIME
 
-#if (SWIG_V8_VERSION < 0x031903)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
 v8::Handle<v8::Value> SWIGV8_AppendOutput(v8::Handle<v8::Value> result, v8::Handle<v8::Value> obj) {
 #else
 v8::Handle<v8::Value> SWIGV8_AppendOutput(v8::Local<v8::Value> result, v8::Handle<v8::Value> obj) {
@@ -610,11 +610,11 @@ v8::Handle<v8::Value> SWIGV8_AppendOutput(v8::Local<v8::Value> result, v8::Handl
   if (result->IsUndefined()) {
     result = SWIGV8_ARRAY_NEW();
   }
-#if (SWIG_V8_VERSION < 0x031903)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
   v8::Handle<v8::Array> arr = v8::Handle<v8::Array>::Cast(result);
 #else  
   v8::Local<v8::Array> arr = v8::Local<v8::Array>::Cast(result);
-#endif  
+#endif
   arr->Set(arr->Length(), obj);
 
   SWIGV8_ESCAPE(arr);
diff --git a/Lib/javascript/v8/javascriptruntime.swg b/Lib/javascript/v8/javascriptruntime.swg
index ea11b0837..0e4059326 100644
--- a/Lib/javascript/v8/javascriptruntime.swg
+++ b/Lib/javascript/v8/javascriptruntime.swg
@@ -5,11 +5,22 @@
 
 // V8 Version Macro
 // ----------------
-// v8 does not (until now) provide a version macro - which is still discussed and may come soon.
-// Until then, we set a default version which can be overridden via command line using V8_VERSION:
-//   swig -javascript -v8 -DV8_VERSION=0x031110
+//
+// v8 added version macros V8_MAJOR_VERSION, V8_MINOR_VERSION, V8_BUILD_NUMBER
+// and V8_PATCH_LEVEL in version 4.3.0.  SWIG generated code uses these if
+// they are defined - to support earlier versions you can specify the V8 version
+// in use via the command line when you run SWIG:
+//
+//   swig -c++ -javascript -v8 -DV8_VERSION=0x032530 example.i
+//
 // Or code in the interface file using SWIG_V8_VERSION:
+//
 //   %begin %{#define SWIG_V8_VERSION 0x031110%}
+//
+// This is specified as a hex constant, but the constant is read as pairs of
+// decimal digits, so for V8 3.25.30 use constant 0x032530.  This scheme can't
+// represent components > 99, but this constant is only useful for V8 < 4.3.0,
+// and no V8 versions from that era had a component > 99.
 
 %define %swig_v8_define_version(version)
 %insert("runtime") %{
diff --git a/Tools/javascript/v8_shell.cxx b/Tools/javascript/v8_shell.cxx
index 7016e9c31..5001bc25a 100644
--- a/Tools/javascript/v8_shell.cxx
+++ b/Tools/javascript/v8_shell.cxx
@@ -13,7 +13,7 @@ typedef int (*V8ExtensionInitializer) (v8::Handle<v8::Object> module);
 
 // Note: these typedefs and defines are used to deal with  v8 API changes since version 3.19.00
 
-#if (SWIG_V8_VERSION < 0x031903)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
 typedef v8::Handle<v8::Value> SwigV8ReturnValue;
 typedef v8::Arguments SwigV8Arguments;
 typedef v8::AccessorInfo SwigV8PropertyCallbackInfo;
@@ -28,11 +28,11 @@ typedef v8::PropertyCallbackInfo<v8::Value> SwigV8PropertyCallbackInfo;
 #endif
 
 
-#if (SWIG_V8_VERSION < 0x032117)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032117)
 #define SWIGV8_HANDLESCOPE() v8::HandleScope scope
 #define SWIGV8_HANDLESCOPE_ESC() v8::HandleScope scope
 #define SWIGV8_ESCAPE(val) return scope.Close(val)
-#elif (SWIG_V8_VERSION < 0x032318)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032318)
 #define SWIGV8_HANDLESCOPE() v8::HandleScope scope(v8::Isolate::GetCurrent());
 #define SWIGV8_HANDLESCOPE_ESC() v8::HandleScope scope(v8::Isolate::GetCurrent());
 #define SWIGV8_ESCAPE(val) return scope.Close(val)
@@ -42,7 +42,7 @@ typedef v8::PropertyCallbackInfo<v8::Value> SwigV8PropertyCallbackInfo;
 #define SWIGV8_ESCAPE(val) return scope.Escape(val)
 #endif
 
-#if (SWIG_V8_VERSION < 0x032318)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032318)
 #define SWIGV8_CURRENT_CONTEXT() v8::Context::GetCurrent()
 #define SWIGV8_STRING_NEW(str) v8::String::New(str)
 #define SWIGV8_FUNCTEMPLATE_NEW(func) v8::FunctionTemplate::New(func)
@@ -59,7 +59,7 @@ typedef v8::PropertyCallbackInfo<v8::Value> SwigV8PropertyCallbackInfo;
 #endif
 
 
-#if (SWIG_V8_VERSION < 0x031900)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
 typedef v8::Persistent<v8::Context> SwigV8Context;
 #else
 typedef v8::Local<v8::Context> SwigV8Context;
@@ -149,9 +149,9 @@ bool V8Shell::RunScript(const std::string &scriptPath) {
 
   context->Exit();
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
     context.Dispose();
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
     context.Dispose(v8::Isolate::GetCurrent());
 #else
 //    context.Dispose();
@@ -193,9 +193,9 @@ bool V8Shell::RunShell() {
 
   context->Exit();
 
-#if (SWIG_V8_VERSION < 0x031710)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031710)
     context.Dispose();
-#elif (SWIG_V8_VERSION < 0x031900)
+#elif (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
     context.Dispose(v8::Isolate::GetCurrent());
 #else
 //    context.Dispose();
@@ -249,7 +249,7 @@ SwigV8Context V8Shell::CreateShellContext() {
   global->Set(SWIGV8_STRING_NEW("require"), SWIGV8_FUNCTEMPLATE_NEW(V8Shell::Require));
   global->Set(SWIGV8_STRING_NEW("version"), SWIGV8_FUNCTEMPLATE_NEW(V8Shell::Version));
 
-#if (SWIG_V8_VERSION < 0x031900)
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031900)
   SwigV8Context context = v8::Context::New(NULL, global);
   return context;
 #else