diff --git a/source/gui/IGUIObject.cpp b/source/gui/IGUIObject.cpp
index bcba14db95..d32cb28743 100644
--- a/source/gui/IGUIObject.cpp
+++ b/source/gui/IGUIObject.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2012 Wildfire Games.
+/* Copyright (C) 2014 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -421,6 +421,8 @@ void IGUIObject::RegisterScriptHandler(const CStr& Action, const CStr& Code, CGU
 		
 	JSContext* cx = pGUI->GetScriptInterface()->GetContext();
 	JSAutoRequest rq(cx);
+	JS::RootedValue globalVal(cx, pGUI->GetGlobalObject());
+	JS::RootedObject globalObj(cx, &globalVal.toObject());
 	
 	const int paramCount = 1;
 	const char* paramNames[paramCount] = { "mouse" };
@@ -433,16 +435,17 @@ void IGUIObject::RegisterScriptHandler(const CStr& Action, const CStr& Code, CGU
 	char buf[64];
 	sprintf_s(buf, ARRAY_SIZE(buf), "__eventhandler%d (%s)", x++, Action.c_str());
 
-	JSFunction* func = JS_CompileFunction(cx, JSVAL_TO_OBJECT(pGUI->GetGlobalObject()),
-		buf, paramCount, paramNames, Code.c_str(), Code.length(), CodeName.c_str(), 0);
+	JS::RootedFunction func(cx, JS_CompileFunction(cx, globalObj,
+		buf, paramCount, paramNames, Code.c_str(), Code.length(), CodeName.c_str(), 0));
 
 	if (!func)
 		return; // JS will report an error message
-
-	SetScriptHandler(Action, JS_GetFunctionObject(func));
+	
+	JS::RootedObject funcObj(cx, JS_GetFunctionObject(func));
+	SetScriptHandler(Action, funcObj);
 }
 
-void IGUIObject::SetScriptHandler(const CStr& Action, JSObject* Function)
+void IGUIObject::SetScriptHandler(const CStr& Action, JS::HandleObject Function)
 {
 	m_ScriptHandlers[Action] = CScriptValRooted(m_pGUI->GetScriptInterface()->GetContext(), JS::ObjectValue(*Function));
 }
@@ -490,7 +493,7 @@ void IGUIObject::ScriptEvent(const CStr& Action)
 	}
 }
 
-void IGUIObject::ScriptEvent(const CStr& Action, const CScriptValRooted& Argument)
+void IGUIObject::ScriptEvent(const CStr& Action, JS::HandleValue Argument)
 {
 	std::map<CStr, CScriptValRooted>::iterator it = m_ScriptHandlers.find(Action);
 	if (it == m_ScriptHandlers.end())
@@ -499,12 +502,13 @@ void IGUIObject::ScriptEvent(const CStr& Action, const CScriptValRooted& Argumen
 	JSContext* cx = m_pGUI->GetScriptInterface()->GetContext();
 	JSAutoRequest rq(cx);
 
-	JSObject* object = GetJSObject();
-
-	jsval arg = Argument.get();
-
-	jsval result;
-	bool ok = JS_CallFunctionValue(cx, object, (*it).second.get(), 1, &arg, &result);
+	JS::AutoValueVector paramData(cx);
+	paramData.append(Argument.get());
+	JS::RootedObject obj(cx, GetJSObject());
+	// TODO: Check if this temporary root can be removed after SpiderMonkey 31 upgrade
+	JS::RootedValue tmpScriptHandler(cx, (*it).second.get());
+	JS::RootedValue result(cx);
+	bool ok = JS_CallFunctionValue(cx, obj, tmpScriptHandler, paramData.length(), paramData.begin(), result.address());
 	if (!ok)
 	{
 		JS_ReportError(cx, "Errors executing script action \"%s\"", Action.c_str());
diff --git a/source/gui/IGUIObject.h b/source/gui/IGUIObject.h
index b03d09aa83..45fa172057 100644
--- a/source/gui/IGUIObject.h
+++ b/source/gui/IGUIObject.h
@@ -455,9 +455,9 @@ protected:
 	 * @param Action Name of action
 	 * @param Argument Argument to pass to action
 	 */
-	void ScriptEvent(const CStr& Action, const CScriptValRooted& Argument);
+	void ScriptEvent(const CStr& Action, JS::HandleValue Argument);
 
-	void SetScriptHandler(const CStr& Action, JSObject* Function);
+	void SetScriptHandler(const CStr& Action, JS::HandleObject Function);
 
 	/**
 	 * Inputes the object that is currently hovered, this function
diff --git a/source/gui/MiniMap.cpp b/source/gui/MiniMap.cpp
index 6e2cde0ee8..df982500ec 100644
--- a/source/gui/MiniMap.cpp
+++ b/source/gui/MiniMap.cpp
@@ -256,7 +256,7 @@ void CMiniMap::FireWorldClickEvent(int button, int clicks)
 	g_GUI->GetActiveGUI()->GetScriptInterface()->Eval("({})", &coords);
 	g_GUI->GetActiveGUI()->GetScriptInterface()->SetProperty(coords, "x", x, false);
 	g_GUI->GetActiveGUI()->GetScriptInterface()->SetProperty(coords, "z", z, false);
-	ScriptEvent("worldclick", CScriptValRooted(cx, coords));
+	ScriptEvent("worldclick", coords);
 
 	UNUSED2(button);
 	UNUSED2(clicks);
diff --git a/source/gui/scripting/JSInterface_IGUIObject.cpp b/source/gui/scripting/JSInterface_IGUIObject.cpp
index 9751089ad0..63647c8f55 100644
--- a/source/gui/scripting/JSInterface_IGUIObject.cpp
+++ b/source/gui/scripting/JSInterface_IGUIObject.cpp
@@ -334,8 +334,9 @@ JSBool JSI_IGUIObject::setProperty(JSContext* cx, JS::HandleObject obj, JS::Hand
 			return JS_FALSE;
 		}
 
+		JS::RootedObject vpObj(cx, &vp.toObject());
 		CStr eventName (CStr(propName.substr(2)).LowerCase());
-		e->SetScriptHandler(eventName, &vp.toObject());
+		e->SetScriptHandler(eventName, vpObj);
 
 		return JS_TRUE;
 	}
@@ -628,7 +629,9 @@ JSBool JSI_IGUIObject::toString(JSContext* cx, uint argc, jsval* vp)
 	JSAutoRequest rq(cx);
 	JS::CallReceiver rec = JS::CallReceiverFromVp(vp);
 
-	IGUIObject* e = (IGUIObject*)JS_GetInstancePrivate(cx, JS_THIS_OBJECT(cx, vp), &JSI_IGUIObject::JSI_class, NULL);
+	JS::RootedObject thisObj(cx, JS_THIS_OBJECT(cx, vp));
+	
+	IGUIObject* e = (IGUIObject*)JS_GetInstancePrivate(cx, thisObj, &JSI_IGUIObject::JSI_class, NULL);
 	if (!e)
 		return JS_FALSE;
 
@@ -645,7 +648,9 @@ JSBool JSI_IGUIObject::focus(JSContext* cx, uint argc, jsval* vp)
 	JSAutoRequest rq(cx);
 	JS::CallReceiver rec = JS::CallReceiverFromVp(vp);
 
-	IGUIObject* e = (IGUIObject*)JS_GetInstancePrivate(cx, JS_THIS_OBJECT(cx, vp), &JSI_IGUIObject::JSI_class, NULL);
+	JS::RootedObject thisObj(cx, JS_THIS_OBJECT(cx, vp));
+	
+	IGUIObject* e = (IGUIObject*)JS_GetInstancePrivate(cx, thisObj, &JSI_IGUIObject::JSI_class, NULL);
 	if (!e)
 		return JS_FALSE;
 
@@ -661,7 +666,9 @@ JSBool JSI_IGUIObject::blur(JSContext* cx, uint argc, jsval* vp)
 	JSAutoRequest rq(cx);
 	JS::CallReceiver rec = JS::CallReceiverFromVp(vp);
 
-	IGUIObject* e = (IGUIObject*)JS_GetInstancePrivate(cx, JS_THIS_OBJECT(cx, vp), &JSI_IGUIObject::JSI_class, NULL);
+	JS::RootedObject thisObj(cx, JS_THIS_OBJECT(cx, vp));
+ 
+	IGUIObject* e = (IGUIObject*)JS_GetInstancePrivate(cx, thisObj, &JSI_IGUIObject::JSI_class, NULL);
 	if (!e)
 		return JS_FALSE;
 
@@ -677,7 +684,9 @@ JSBool JSI_IGUIObject::getComputedSize(JSContext* cx, uint argc, jsval* vp)
 	JSAutoRequest rq(cx);
 	JS::CallReceiver rec = JS::CallReceiverFromVp(vp);
 	
-	IGUIObject* e = (IGUIObject*)JS_GetInstancePrivate(cx, JS_THIS_OBJECT(cx, vp), &JSI_IGUIObject::JSI_class, NULL);
+	JS::RootedObject thisObj(cx, JS_THIS_OBJECT(cx, vp));
+	
+	IGUIObject* e = (IGUIObject*)JS_GetInstancePrivate(cx, thisObj, &JSI_IGUIObject::JSI_class, NULL);
 	if (!e)
 		return JS_FALSE;