From 86c151ebaabf4d2a89065fe2c99c2c430354642a Mon Sep 17 00:00:00 2001
From: elexis <elexis@wildfiregames.com>
Date: Fri, 16 Aug 2019 18:46:04 +0000
Subject: [PATCH] PushGuiPage support for passing a function instead of a
 function name.

Allows coding the GUI without global functions which break
prototype-oriented coding, refs #5322, fixing the concern in 4b1297b328.

Supports stacked message boxes and removes the according workaround.
Change structree / civinfo switch-dialog code from 760a47335d to perform
the callback for page that actually registered the callback.
Ensure the parent that the callbackhandler is always called if the page
is closed.
Merge PopGuiPage and PopGuiPageCB following that choice, incidentally
leaving cleaner code.

Differential Revision: https://code.wildfiregames.com/D1684
Comments by: Yves, Vladislav, wraitii, leper
This was SVN commit r22676.
---
 .../mods/mod/gui/common/functions_msgbox.js   |  58 +++-------
 binaries/data/mods/mod/gui/common/terms.js    |  37 +++---
 binaries/data/mods/mod/gui/modio/modio.js     |   4 +-
 binaries/data/mods/mod/gui/modmod/modmodio.js |   4 +-
 binaries/data/mods/mod/gui/msgbox/msgbox.js   |  15 +--
 .../mods/mod/gui/termsdialog/termsdialog.js   |   2 +-
 .../data/mods/public/gui/aiconfig/aiconfig.js |   5 +-
 .../data/mods/public/gui/civinfo/civinfo.js   |  16 +--
 .../mods/public/gui/gamesetup/gamesetup.js    |  57 ++++-----
 .../mods/public/gui/gamesetup/gamesetup.xml   |   8 +-
 .../data/mods/public/gui/locale/locale.js     |   2 +-
 .../gui/locale_advanced/locale_advanced.js    |   2 +-
 .../data/mods/public/gui/manual/manual.js     |  15 ---
 .../data/mods/public/gui/manual/manual.xml    |   7 +-
 .../data/mods/public/gui/options/options.js   |  17 +--
 .../data/mods/public/gui/pregame/mainmenu.js  |  16 ++-
 .../data/mods/public/gui/pregame/mainmenu.xml |  10 +-
 .../mods/public/gui/reference/common/core.js  |   9 --
 .../gui/reference/structree/structree.js      |  16 +--
 .../public/gui/reference/viewer/viewer.js     |   6 -
 .../public/gui/reference/viewer/viewer.xml    |   2 +-
 .../data/mods/public/gui/savegame/save.js     |   2 +-
 .../mods/public/gui/session/hotkeys/misc.xml  |   8 +-
 binaries/data/mods/public/gui/session/menu.js |  88 +++++++-------
 .../public/gui/session/selection_panels.js    |  12 +-
 .../public/gui/session/top_panel/civ_icon.xml |   2 +-
 .../public/gui/splashscreen/splashscreen.js   |   2 +-
 .../data/mods/public/gui/summary/summary.js   |   2 +-
 source/gui/GUIManager.cpp                     | 108 +++++++++---------
 source/gui/GUIManager.h                       |  30 ++++-
 .../gui/scripting/JSInterface_GUIManager.cpp  |  20 ++--
 source/gui/scripting/JSInterface_GUIManager.h |   5 +-
 32 files changed, 258 insertions(+), 329 deletions(-)
 delete mode 100644 binaries/data/mods/public/gui/manual/manual.js

diff --git a/binaries/data/mods/mod/gui/common/functions_msgbox.js b/binaries/data/mods/mod/gui/common/functions_msgbox.js
index f289749a72..acf524bff3 100644
--- a/binaries/data/mods/mod/gui/common/functions_msgbox.js
+++ b/binaries/data/mods/mod/gui/common/functions_msgbox.js
@@ -1,50 +1,18 @@
-// We want to pass callback functions for the different buttons in a convenient way.
-// Because passing functions accross compartment boundaries is a pain, we just store them here together with some optional arguments.
-// The messageBox page will return the code of the pressed button and the according function will be called.
-var g_MessageBoxBtnFunctions = [];
-var g_MessageBoxCallbackArgs = [];
-
-function messageBoxCallbackFunction(btnCode)
-{
-	if (btnCode !== undefined && g_MessageBoxBtnFunctions[btnCode])
-	{
-		// Cache the variables to make it possible to call a messageBox from a callback function.
-		let callbackFunction = g_MessageBoxBtnFunctions[btnCode];
-		let callbackArgs = g_MessageBoxCallbackArgs[btnCode];
-
-		g_MessageBoxBtnFunctions = [];
-		g_MessageBoxCallbackArgs = [];
-
-		if (callbackArgs !== undefined)
-			callbackFunction(callbackArgs);
-		else
-			callbackFunction();
-		return;
-	}
-
-	g_MessageBoxBtnFunctions = [];
-	g_MessageBoxCallbackArgs = [];
-}
-
 function messageBox(mbWidth, mbHeight, mbMessage, mbTitle, mbButtonCaptions, mbBtnCode, mbCallbackArgs)
 {
-	if (g_MessageBoxBtnFunctions && g_MessageBoxBtnFunctions.length)
-	{
-		warn("A messagebox was called when a previous callback function is still set, aborting!");
-		return;
-	}
-
-	g_MessageBoxBtnFunctions = mbBtnCode;
-	g_MessageBoxCallbackArgs = mbCallbackArgs || g_MessageBoxCallbackArgs;
-
-	Engine.PushGuiPage("page_msgbox.xml", {
-		"width": mbWidth,
-		"height": mbHeight,
-		"message": mbMessage,
-		"title": mbTitle,
-		"buttonCaptions": mbButtonCaptions,
-		"callback": mbBtnCode && "messageBoxCallbackFunction"
-	});
+	Engine.PushGuiPage(
+		"page_msgbox.xml",
+		{
+			"width": mbWidth,
+			"height": mbHeight,
+			"message": mbMessage,
+			"title": mbTitle,
+			"buttonCaptions": mbButtonCaptions
+		},
+		btnCode => {
+			if (mbBtnCode !== undefined && mbBtnCode[btnCode])
+				mbBtnCode[btnCode](mbCallbackArgs ? mbCallbackArgs[btnCode] : undefined);
+		});
 }
 
 function openURL(url)
diff --git a/binaries/data/mods/mod/gui/common/terms.js b/binaries/data/mods/mod/gui/common/terms.js
index 6992d7056c..6d6a4b7a6b 100644
--- a/binaries/data/mods/mod/gui/common/terms.js
+++ b/binaries/data/mods/mod/gui/common/terms.js
@@ -7,24 +7,29 @@ function initTerms(terms)
 
 function openTerms(page)
 {
-	Engine.PushGuiPage("page_termsdialog.xml", {
-		"file": g_Terms[page].file,
-		"title": g_Terms[page].title,
-		"sprintf": g_Terms[page].sprintf,
-		"urlButtons": g_Terms[page].urlButtons || [],
-		"termsURL": g_Terms[page].termsURL || undefined,
-		"page": page,
-		"callback": "acceptTerms"
-	});
-}
+	Engine.PushGuiPage(
+		"page_termsdialog.xml",
+		{
+			"file": g_Terms[page].file,
+			"title": g_Terms[page].title,
+			"sprintf": g_Terms[page].sprintf,
+			"urlButtons": g_Terms[page].urlButtons || [],
+			"termsURL": g_Terms[page].termsURL || undefined,
+			"page": page
+		},
+		data => {
+			g_Terms[data.page].accepted = data.accepted;
 
-function acceptTerms(data)
-{
-	g_Terms[data.page].accepted = data.accepted;
-	Engine.ConfigDB_CreateAndWriteValueToFile("user", g_Terms[data.page].config, data.accepted ? getTermsHash(data.page) : "0", "config/user.cfg");
+			Engine.ConfigDB_CreateAndWriteValueToFile(
+				"user",
+				g_Terms[data.page].config,
+				data.accepted ? getTermsHash(data.page) : "0",
+				"config/user.cfg");
 
-	if (g_Terms[data.page].callback)
-		g_Terms[data.page].callback(data);
+			if (g_Terms[data.page].callback)
+				g_Terms[data.page].callback(data);
+		}
+	);
 }
 
 function checkTerms()
diff --git a/binaries/data/mods/mod/gui/modio/modio.js b/binaries/data/mods/mod/gui/modio/modio.js
index c31c5912eb..f5cc5b9837 100644
--- a/binaries/data/mods/mod/gui/modio/modio.js
+++ b/binaries/data/mods/mod/gui/modio/modio.js
@@ -268,9 +268,9 @@ function cancelRequest()
 	hideDialog();
 }
 
-function closePage(data)
+function closePage()
 {
-	Engine.PopGuiPageCB(undefined);
+	Engine.PopGuiPage();
 }
 
 function showErrorMessageBox(caption, title, buttonCaptions, buttonActions)
diff --git a/binaries/data/mods/mod/gui/modmod/modmodio.js b/binaries/data/mods/mod/gui/modmod/modmodio.js
index 3125b41029..b3e69f1044 100644
--- a/binaries/data/mods/mod/gui/modmod/modmodio.js
+++ b/binaries/data/mods/mod/gui/modmod/modmodio.js
@@ -26,7 +26,5 @@ function downloadModsButton()
 function openModIo(data)
 {
 	if (data.accepted)
-		Engine.PushGuiPage("page_modio.xml", {
-			"callback": "initMods"
-		});
+		Engine.PushGuiPage("page_modio.xml", {}, initMods);
 }
diff --git a/binaries/data/mods/mod/gui/msgbox/msgbox.js b/binaries/data/mods/mod/gui/msgbox/msgbox.js
index 58f2b09356..9276a482c6 100644
--- a/binaries/data/mods/mod/gui/msgbox/msgbox.js
+++ b/binaries/data/mods/mod/gui/msgbox/msgbox.js
@@ -28,22 +28,15 @@ function init(data)
 	let mbButton = [];
 	captions.forEach((caption, i) => {
 		mbButton[i] = Engine.GetGUIObjectByName("mbButton" + (i + 1));
-
-		let action = function()
-		{
-			if (data.callback)
-				Engine.PopGuiPageCB(i);
-			else
-				Engine.PopGuiPage();
-		};
-
 		mbButton[i].caption = caption;
-		mbButton[i].onPress = action;
 		mbButton[i].hidden = false;
+		mbButton[i].onPress = () => {
+			Engine.PopGuiPage(i);
+		};
 
 		// Convention: Cancel is the first button
 		if (i == 0)
-			mbCancelHotkey.onPress = action;
+			mbCancelHotkey.onPress = mbButton[i].onPress;
 	});
 
 	// Distribute buttons horizontally
diff --git a/binaries/data/mods/mod/gui/termsdialog/termsdialog.js b/binaries/data/mods/mod/gui/termsdialog/termsdialog.js
index 818b19039f..4420e990bb 100644
--- a/binaries/data/mods/mod/gui/termsdialog/termsdialog.js
+++ b/binaries/data/mods/mod/gui/termsdialog/termsdialog.js
@@ -82,7 +82,7 @@ function initLanguageSelection()
 
 function closeTerms(accepted)
 {
-	Engine.PopGuiPageCB({
+	Engine.PopGuiPage({
 		"page": g_TermsPage,
 		"accepted": accepted
 	});
diff --git a/binaries/data/mods/public/gui/aiconfig/aiconfig.js b/binaries/data/mods/public/gui/aiconfig/aiconfig.js
index 9d44575564..5a3bb81d4f 100644
--- a/binaries/data/mods/public/gui/aiconfig/aiconfig.js
+++ b/binaries/data/mods/public/gui/aiconfig/aiconfig.js
@@ -69,10 +69,7 @@ function checkBehavior()
 function returnAI(save = true)
 {
 	let idx = Engine.GetGUIObjectByName("aiSelection").selected;
-
-	// Pop the page before calling the callback, so the callback runs
-	// in the parent GUI page's context
-	Engine.PopGuiPageCB({
+	Engine.PopGuiPage({
 		"save": save,
 		"id": g_AIDescriptions[idx].id,
 		"name": g_AIDescriptions[idx].data.name,
diff --git a/binaries/data/mods/public/gui/civinfo/civinfo.js b/binaries/data/mods/public/gui/civinfo/civinfo.js
index f20d78012a..2dbc5d81ee 100644
--- a/binaries/data/mods/public/gui/civinfo/civinfo.js
+++ b/binaries/data/mods/public/gui/civinfo/civinfo.js
@@ -3,11 +3,6 @@
  */
 const g_CivData = loadCivData(true, false);
 
-/**
- * Callback function name on closing gui via Engine.PopGuiPage().
- */
-var g_Callback = "";
-
 var g_SelectedCiv = "";
 
 /**
@@ -15,9 +10,6 @@ var g_SelectedCiv = "";
  */
 function init(data = {})
 {
-	if (data.callback)
-		g_Callback = data.callback;
-
 	var civList = Object.keys(g_CivData).map(civ => ({ "name": g_CivData[civ].Name, "code": civ })).sort(sortNameIgnoreCase);
 	var civSelection = Engine.GetGUIObjectByName("civSelection");
 
@@ -94,16 +86,12 @@ function subHeading(obj)
 
 function switchToStrucTreePage()
 {
-	Engine.PopGuiPage();
-	Engine.PushGuiPage("page_structree.xml", { "civ": g_SelectedCiv, "callback": g_Callback });
+	Engine.PopGuiPage({ "civ": g_SelectedCiv, "nextPage": "page_structree.xml" });
 }
 
 function closePage()
 {
-	if (g_Callback)
-		Engine.PopGuiPageCB({ "civ": g_SelectedCiv, "page": "page_civinfo.xml" });
-	else
-		Engine.PopGuiPage();
+	Engine.PopGuiPage({ "civ": g_SelectedCiv, "page": "page_civinfo.xml" });
 }
 
 /**
diff --git a/binaries/data/mods/public/gui/gamesetup/gamesetup.js b/binaries/data/mods/public/gui/gamesetup/gamesetup.js
index 1567bf68c3..a3953cd6ec 100644
--- a/binaries/data/mods/public/gui/gamesetup/gamesetup.js
+++ b/binaries/data/mods/public/gui/gamesetup/gamesetup.js
@@ -22,7 +22,7 @@ const g_CivData = loadCivData(false, false);
  * Store civilization code and page (structree or history) opened in civilization info.
  */
 var g_CivInfo = {
-	"code": "",
+	"civ": "",
 	"page": "page_civinfo.xml"
 };
 
@@ -1047,10 +1047,10 @@ var g_MiscControls = {
 				"hotkey_structree": colorizeHotkey("%(hotkey)s", "structree")
 			}),
 		"onPress": () => function() {
-			Engine.PushGuiPage(g_CivInfo.page, {
-				"civ": g_CivInfo.code,
-				"callback": "storeCivInfoPage"
-			});
+			Engine.PushGuiPage(
+				g_CivInfo.page,
+				{ "civ": g_CivInfo.civ },
+				storeCivInfoPage);
 		}
 	},
 	"civResetButton": {
@@ -2423,30 +2423,26 @@ function openAIConfig(playerSlot)
 {
 	g_LastViewedAIPlayer = playerSlot;
 
-	Engine.PushGuiPage("page_aiconfig.xml", {
-		"callback": "AIConfigCallback",
-		"playerSlot": playerSlot,
-		"id": g_GameAttributes.settings.PlayerData[playerSlot].AI,
-		"difficulty": g_GameAttributes.settings.PlayerData[playerSlot].AIDiff,
-		"behavior": g_GameAttributes.settings.PlayerData[playerSlot].AIBehavior
-	});
-}
+	Engine.PushGuiPage(
+		"page_aiconfig.xml",
+		{
+			"playerSlot": playerSlot,
+			"id": g_GameAttributes.settings.PlayerData[playerSlot].AI,
+			"difficulty": g_GameAttributes.settings.PlayerData[playerSlot].AIDiff,
+			"behavior": g_GameAttributes.settings.PlayerData[playerSlot].AIBehavior
+		},
+		ai => {
+			g_LastViewedAIPlayer = -1;
 
-/**
- * Called after closing the dialog.
- */
-function AIConfigCallback(ai)
-{
-	g_LastViewedAIPlayer = -1;
+			if (!ai.save || !g_IsController)
+				return;
 
-	if (!ai.save || !g_IsController)
-		return;
+			g_GameAttributes.settings.PlayerData[ai.playerSlot].AI = ai.id;
+			g_GameAttributes.settings.PlayerData[ai.playerSlot].AIDiff = ai.difficulty;
+			g_GameAttributes.settings.PlayerData[ai.playerSlot].AIBehavior = ai.behavior;
 
-	g_GameAttributes.settings.PlayerData[ai.playerSlot].AI = ai.id;
-	g_GameAttributes.settings.PlayerData[ai.playerSlot].AIDiff = ai.difficulty;
-	g_GameAttributes.settings.PlayerData[ai.playerSlot].AIBehavior = ai.behavior;
-
-	updateGameAttributes();
+			updateGameAttributes();
+		});
 }
 
 function reloadPlayerAssignmentChoices()
@@ -2775,6 +2771,11 @@ function updateAutocompleteEntries()
 
 function storeCivInfoPage(data)
 {
-	g_CivInfo.code = data.civ;
-	g_CivInfo.page = data.page;
+	if (data.nextPage)
+		Engine.PushGuiPage(
+			data.nextPage,
+			{ "civ": data.civ },
+			storeCivInfoPage);
+	else
+		g_CivInfo = data;
 }
diff --git a/binaries/data/mods/public/gui/gamesetup/gamesetup.xml b/binaries/data/mods/public/gui/gamesetup/gamesetup.xml
index 5b3aeee277..5c3538b3b3 100644
--- a/binaries/data/mods/public/gui/gamesetup/gamesetup.xml
+++ b/binaries/data/mods/public/gui/gamesetup/gamesetup.xml
@@ -6,15 +6,11 @@
 	<script directory="gui/gamesetup/"/>
 
 	<object	hotkey="civinfo">
-		<action on="Press">
-			Engine.PushGuiPage("page_civinfo.xml", { "civ": g_CivInfo.code, "callback": "storeCivInfoPage" });
-		</action>
+		<action on="Press">Engine.PushGuiPage("page_civinfo.xml", { "civ": g_CivInfo.civ }, storeCivInfoPage);</action>
 	</object>
 
 	<object	hotkey="structree">
-		<action on="Press">
-			Engine.PushGuiPage("page_structree.xml", { "civ": g_CivInfo.code, "callback": "storeCivInfoPage" });
-		</action>
+		<action on="Press">Engine.PushGuiPage("page_structree.xml", { "civ": g_CivInfo.civ }, storeCivInfoPage);</action>
 	</object>
 
 	<object hotkey="cancel">
diff --git a/binaries/data/mods/public/gui/locale/locale.js b/binaries/data/mods/public/gui/locale/locale.js
index a98bd0a6e2..a5c3dc844c 100644
--- a/binaries/data/mods/public/gui/locale/locale.js
+++ b/binaries/data/mods/public/gui/locale/locale.js
@@ -55,7 +55,7 @@ function languageSelectionChanged()
 function openAdvancedMenu()
 {
 	let localeText = Engine.GetGUIObjectByName("localeText");
-	Engine.PushGuiPage("page_locale_advanced.xml", { "callback": "applyFromAdvancedMenu", "locale": localeText.caption });
+	Engine.PushGuiPage("page_locale_advanced.xml", { "locale": localeText.caption }, applyFromAdvancedMenu);
 }
 
 function applyFromAdvancedMenu(locale)
diff --git a/binaries/data/mods/public/gui/locale_advanced/locale_advanced.js b/binaries/data/mods/public/gui/locale_advanced/locale_advanced.js
index c47463ed1d..a19daf3877 100644
--- a/binaries/data/mods/public/gui/locale_advanced/locale_advanced.js
+++ b/binaries/data/mods/public/gui/locale_advanced/locale_advanced.js
@@ -114,5 +114,5 @@ function autoDetectLocale()
 function applySelectedLocale()
 {
 	var resultingLocaleText = Engine.GetGUIObjectByName("resultingLocale");
-	Engine.PopGuiPageCB(resultingLocaleText.caption);
+	Engine.PopGuiPage(resultingLocaleText.caption);
 }
diff --git a/binaries/data/mods/public/gui/manual/manual.js b/binaries/data/mods/public/gui/manual/manual.js
deleted file mode 100644
index 3f7a897c4a..0000000000
--- a/binaries/data/mods/public/gui/manual/manual.js
+++ /dev/null
@@ -1,15 +0,0 @@
-var hasCallback = false;
-
-function init(data)
-{
-	Engine.GetGUIObjectByName("mainText").caption = Engine.TranslateLines(Engine.ReadFile("gui/manual/intro.txt"));
-	hasCallback = data && data.callback;
-}
-
-function closeManual()
-{
-	if (hasCallback)
-		Engine.PopGuiPageCB();
-	else
-		Engine.PopGuiPage();
-}
diff --git a/binaries/data/mods/public/gui/manual/manual.xml b/binaries/data/mods/public/gui/manual/manual.xml
index cb82f27887..fde7773ae2 100644
--- a/binaries/data/mods/public/gui/manual/manual.xml
+++ b/binaries/data/mods/public/gui/manual/manual.xml
@@ -14,13 +14,16 @@
 		</object>
 
 		<object type="image" sprite="ModernFade" size="20 20 100%-20 100%-58">
-			<object name="mainText" type="text" style="ModernTextPanel"/>
+			<object name="mainText" type="text" style="ModernTextPanel">
+				<action on="Load">this.caption = Engine.TranslateLines(Engine.ReadFile("gui/manual/intro.txt"));</action>
+			</object>
 		</object>
 
 		<object type="button" style="ModernButtonRed" tooltip_style="snToolTip" size="100%-408 100%-52 100%-218 100%-24" hotkey="cancel">
 			<translatableAttribute id="caption">Close</translatableAttribute>
-			<action on="Press">closeManual();</action>
+			<action on="Press">Engine.PopGuiPage();</action>
 		</object>
+
 		<object name="url" type="button" style="ModernButtonRed" size="100%-214 100%-52 100%-24 100%-24">
 			<translatableAttribute id="caption">View Online</translatableAttribute>
 			<action on="Press">openURL("https://trac.wildfiregames.com/wiki/0adManual");</action>
diff --git a/binaries/data/mods/public/gui/options/options.js b/binaries/data/mods/public/gui/options/options.js
index 0f541b8eda..bd30f3e635 100644
--- a/binaries/data/mods/public/gui/options/options.js
+++ b/binaries/data/mods/public/gui/options/options.js
@@ -4,12 +4,7 @@
 var g_Options;
 
 /**
- * Remember whether to unpause running singleplayer games.
- */
-var g_HasCallback;
-
-/**
- * Functions to call after closing the page.
+ * Names of session functions to be called after closing the page.
  */
 var g_CloseCallbacks;
 
@@ -170,8 +165,7 @@ var g_OptionType = {
 
 function init(data, hotloadData)
 {
-	g_CloseCallbacks = new Set();
-	g_HasCallback = hotloadData && hotloadData.callback || data && data.callback;
+	g_CloseCallbacks = hotloadData ? hotloadData.closeCallbacks : new Set();
 	g_TabCategorySelected = hotloadData ? hotloadData.tabCategorySelected : 0;
 
 	g_Options = Engine.ReadJSONFile("gui/options/options.json");
@@ -190,7 +184,7 @@ function getHotloadData()
 {
 	return {
 		"tabCategorySelected": g_TabCategorySelected,
-		"callback": g_HasCallback
+		"closeCallbacks": g_CloseCallbacks
 	};
 }
 
@@ -382,8 +376,5 @@ function closePage()
 
 function closePageWithoutConfirmation()
 {
-	if (g_HasCallback)
-		Engine.PopGuiPageCB(g_CloseCallbacks);
-	else
-		Engine.PopGuiPage();
+	Engine.PopGuiPage(g_CloseCallbacks);
 }
diff --git a/binaries/data/mods/public/gui/pregame/mainmenu.js b/binaries/data/mods/public/gui/pregame/mainmenu.js
index dda81b84d7..3120fcc715 100644
--- a/binaries/data/mods/public/gui/pregame/mainmenu.js
+++ b/binaries/data/mods/public/gui/pregame/mainmenu.js
@@ -105,9 +105,7 @@ function onTick()
 
 function ShowSplashScreen()
 {
-	Engine.PushGuiPage("page_splashscreen.xml", {
-		"callback": "ShowRenderPathMessage"
-	});
+	Engine.PushGuiPage("page_splashscreen.xml", {}, ShowRenderPathMessage);
 }
 
 function ShowRenderPathMessage()
@@ -232,3 +230,15 @@ function getLobbyDisabledByBuild()
 {
 	return translate("Launch the multiplayer lobby to join and host publicly visible games and chat with other players. \\[DISABLED BY BUILD]");
 }
+
+function openStrucTree(page)
+{
+	closeMenu();
+	Engine.PushGuiPage(page, {}, storeCivInfoPage);
+}
+
+function storeCivInfoPage(data)
+{
+	if (data.nextPage)
+		Engine.PushGuiPage(data.nextPage, { "civ": data.civ }, storeCivInfoPage);
+}
diff --git a/binaries/data/mods/public/gui/pregame/mainmenu.xml b/binaries/data/mods/public/gui/pregame/mainmenu.xml
index 57be3592ea..3c7e10c58b 100644
--- a/binaries/data/mods/public/gui/pregame/mainmenu.xml
+++ b/binaries/data/mods/public/gui/pregame/mainmenu.xml
@@ -118,10 +118,7 @@
 					hotkey="structree"
 				>
 					<translatableAttribute id="caption">Structure Tree</translatableAttribute>
-					<action on="Press">
-						closeMenu();
-						Engine.PushGuiPage("page_structree.xml", {});
-					</action>
+					<action on="Press">openStrucTree("page_structree.xml");</action>
 				</object>
 
 				<!-- HISTORY BUTTON -->
@@ -134,10 +131,7 @@
 					hotkey="civinfo"
 				>
 					<translatableAttribute id="caption">History</translatableAttribute>
-					<action on="Press">
-						closeMenu();
-						Engine.PushGuiPage("page_civinfo.xml");
-					</action>
+					<action on="Press">openStrucTree("page_civinfo.xml");</action>
 				</object>
 
 			</object>
diff --git a/binaries/data/mods/public/gui/reference/common/core.js b/binaries/data/mods/public/gui/reference/common/core.js
index 51f92d2ada..8e50996a84 100644
--- a/binaries/data/mods/public/gui/reference/common/core.js
+++ b/binaries/data/mods/public/gui/reference/common/core.js
@@ -1,13 +1,4 @@
 var g_SelectedCiv = "gaia";
-var g_CallbackSet = false;
-
-function closePage()
-{
-	if (g_CallbackSet)
-		Engine.PopGuiPageCB(0);
-	else
-		Engine.PopGuiPage();
-}
 
 /**
  * Compile lists of templates buildable/trainable/researchable of a given civ.
diff --git a/binaries/data/mods/public/gui/reference/structree/structree.js b/binaries/data/mods/public/gui/reference/structree/structree.js
index a8e1368db6..2267dc32a9 100644
--- a/binaries/data/mods/public/gui/reference/structree/structree.js
+++ b/binaries/data/mods/public/gui/reference/structree/structree.js
@@ -8,11 +8,6 @@ var g_BuildList = {};
  */
 var g_TrainList = {};
 
-/**
- * Callback function name on closing gui via Engine.PopGuiPage().
- */
-var g_Callback = "";
-
 /**
  * Initialize the page
  *
@@ -20,9 +15,6 @@ var g_Callback = "";
  */
 function init(data = {})
 {
-	if (data.callback)
-		g_Callback = data.callback;
-
 	let civList = Object.keys(g_CivData).map(civ => ({
 		"name": g_CivData[civ].Name,
 		"code": civ,
@@ -52,16 +44,12 @@ function init(data = {})
 
 function switchToCivInfoPage()
 {
-	Engine.PopGuiPage();
-	Engine.PushGuiPage("page_civinfo.xml", { "civ": g_SelectedCiv, "callback": g_Callback });
+	Engine.PopGuiPage({ "civ": g_SelectedCiv, "nextPage": "page_civinfo.xml" });
 }
 
 function closePage()
 {
-	if (g_Callback)
-		Engine.PopGuiPageCB({ "civ": g_SelectedCiv, "page": "page_structree.xml" });
-	else
-		Engine.PopGuiPage();
+	Engine.PopGuiPage({ "civ": g_SelectedCiv, "page": "page_structree.xml" });
 }
 
 /**
diff --git a/binaries/data/mods/public/gui/reference/viewer/viewer.js b/binaries/data/mods/public/gui/reference/viewer/viewer.js
index 68f5085953..e269463046 100644
--- a/binaries/data/mods/public/gui/reference/viewer/viewer.js
+++ b/binaries/data/mods/public/gui/reference/viewer/viewer.js
@@ -47,9 +47,6 @@ var g_RankIconPath = "session/icons/ranks/";
  * @param {object} data - Contains the civCode and the name of the template to display.
  * @param {string} data.templateName
  * @param {string} [data.civ]
- * @param {*} [data.callback] - If set and loosely equivalent to true, a callback is
- *                              assumed to be setup ready be called by the Engine upon
- *                              closure of this page.
  */
 function init(data)
 {
@@ -60,9 +57,6 @@ function init(data)
 		return;
 	}
 
-	if (data.callback)
-		g_CallbackSet = true;
-
 	let templateName = removeFiltersFromTemplateName(data.templateName);
 	let isTech = techDataExists(templateName);
 
diff --git a/binaries/data/mods/public/gui/reference/viewer/viewer.xml b/binaries/data/mods/public/gui/reference/viewer/viewer.xml
index 40b8cfbb79..db918ef23c 100644
--- a/binaries/data/mods/public/gui/reference/viewer/viewer.xml
+++ b/binaries/data/mods/public/gui/reference/viewer/viewer.xml
@@ -35,7 +35,7 @@
 			hotkey="cancel"
 		>
 			<translatableAttribute id="caption">Close</translatableAttribute>
-			<action on="Press">closePage();</action>
+			<action on="Press">Engine.PopGuiPage();</action>
 		</object>
 	</object>
 
diff --git a/binaries/data/mods/public/gui/savegame/save.js b/binaries/data/mods/public/gui/savegame/save.js
index fea4675a8d..1325e7750e 100644
--- a/binaries/data/mods/public/gui/savegame/save.js
+++ b/binaries/data/mods/public/gui/savegame/save.js
@@ -80,7 +80,7 @@ function reallySaveGame(name, desc, nameIsPrefix)
 
 function closeSave()
 {
-	Engine.PopGuiPageCB(0);
+	Engine.PopGuiPage();
 }
 
 // HACK: Engine.SaveGame* expects this function to be defined on the current page.
diff --git a/binaries/data/mods/public/gui/session/hotkeys/misc.xml b/binaries/data/mods/public/gui/session/hotkeys/misc.xml
index 07049c0b6e..28c3b17288 100644
--- a/binaries/data/mods/public/gui/session/hotkeys/misc.xml
+++ b/binaries/data/mods/public/gui/session/hotkeys/misc.xml
@@ -33,15 +33,11 @@
 	</object>
 
 	<object	hotkey="civinfo">
-		<action on="Press">
-			Engine.PushGuiPage("page_civinfo.xml", { "civ": g_CivInfo.code, "callback": "storeCivInfoPage" });
-		</action>
+		<action on="Press">openStrucTree("page_civinfo.xml");</action>
 	</object>
 
 	<object	hotkey="structree">
-		<action on="Press">
-			Engine.PushGuiPage("page_structree.xml", { "civ": g_CivInfo.code, "callback": "storeCivInfoPage" });
-		</action>
+		<action on="Press">openStrucTree("page_structree.xml");</action>
 	</object>
 
 	<object hotkey="silhouettes">
diff --git a/binaries/data/mods/public/gui/session/menu.js b/binaries/data/mods/public/gui/session/menu.js
index 0cc871a88a..a1bf783b22 100644
--- a/binaries/data/mods/public/gui/session/menu.js
+++ b/binaries/data/mods/public/gui/session/menu.js
@@ -29,7 +29,7 @@ var g_IdleTraderTextColor = "orange";
  * Store civilization code and page (structree or history) opened in civilization info.
  */
 var g_CivInfo = {
-	"code": "",
+	"civ": "",
 	"page": "page_structree.xml"
 };
 
@@ -225,10 +225,10 @@ function openSave()
 	closeOpenDialogs();
 	pauseGame();
 
-	Engine.PushGuiPage("page_savegame.xml", {
-		"savedGameData": getSavedGameData(),
-		"callback": "resumeGame"
-	});
+	Engine.PushGuiPage(
+		"page_savegame.xml",
+		{ "savedGameData": getSavedGameData() },
+		resumeGame);
 }
 
 function openOptions()
@@ -236,18 +236,16 @@ function openOptions()
 	closeOpenDialogs();
 	pauseGame();
 
-	Engine.PushGuiPage("page_options.xml", {
-		"callback": "optionsPageClosed"
-	});
-}
+	Engine.PushGuiPage(
+		"page_options.xml",
+		{},
+		callbackFunctionNames => {
+			for (let functionName of callbackFunctionNames)
+				if (global[functionName])
+					global[functionName]();
 
-function optionsPageClosed(data)
-{
-	for (let callback of data)
-		if (global[callback])
-			global[callback]();
-
-	resumeGame();
+			resumeGame();
+		});
 }
 
 function openChat(command = "")
@@ -1090,41 +1088,51 @@ function openGameSummary()
 	pauseGame();
 
 	let extendedSimState = Engine.GuiInterfaceCall("GetExtendedSimulationState");
-	Engine.PushGuiPage("page_summary.xml", {
-		"sim": {
-			"mapSettings": g_GameAttributes.settings,
-			"playerStates": extendedSimState.players.filter((state, player) =>
-				g_IsObserver || player == 0 || player == g_ViewedPlayer ||
-				extendedSimState.players[g_ViewedPlayer].hasSharedLos && g_Players[player].isMutualAlly[g_ViewedPlayer]),
-			"timeElapsed": extendedSimState.timeElapsed
+	Engine.PushGuiPage(
+		"page_summary.xml",
+		{
+			"sim": {
+				"mapSettings": g_GameAttributes.settings,
+				"playerStates": extendedSimState.players.filter((state, player) =>
+					g_IsObserver || player == 0 || player == g_ViewedPlayer ||
+					extendedSimState.players[g_ViewedPlayer].hasSharedLos && g_Players[player].isMutualAlly[g_ViewedPlayer]),
+				"timeElapsed": extendedSimState.timeElapsed
+			},
+			"gui": {
+				"dialog": true,
+				"isInGame": true
+			},
+			"selectedData": g_SummarySelectedData
 		},
-		"gui": {
-			"dialog": true,
-			"isInGame": true
-		},
-		"selectedData": g_SummarySelectedData,
-		"callback": "resumeGameAndSaveSummarySelectedData"
-	});
+		resumeGameAndSaveSummarySelectedData);
 }
 
-function openStrucTree()
+function openStrucTree(page)
 {
 	closeOpenDialogs();
 	pauseGame();
 
-	// TODO add info about researched techs and unlocked entities
-
-	Engine.PushGuiPage(g_CivInfo.page, {
-		"civ": g_CivInfo.code || g_Players[g_ViewedPlayer].civ,
-		"callback": "storeCivInfoPage"
-	});
+	Engine.PushGuiPage(
+		page,
+		{
+			"civ": g_CivInfo.civ || g_Players[g_ViewedPlayer].civ
+			// TODO add info about researched techs and unlocked entities
+		},
+		storeCivInfoPage);
 }
 
 function storeCivInfoPage(data)
 {
-	g_CivInfo.code = data.civ;
-	g_CivInfo.page = data.page;
-	resumeGame();
+	if (data.nextPage)
+		Engine.PushGuiPage(
+			data.nextPage,
+			{ "civ": data.civ },
+			storeCivInfoPage);
+	else
+	{
+		g_CivInfo = data;
+		resumeGame();
+	}
 }
 
 /**
diff --git a/binaries/data/mods/public/gui/session/selection_panels.js b/binaries/data/mods/public/gui/session/selection_panels.js
index aa7626b227..df1deffa05 100644
--- a/binaries/data/mods/public/gui/session/selection_panels.js
+++ b/binaries/data/mods/public/gui/session/selection_panels.js
@@ -1143,11 +1143,13 @@ function showTemplateDetails(templateName, civCode)
 {
 	pauseGame();
 
-	Engine.PushGuiPage("page_viewer.xml", {
-		"templateName": templateName,
-		"callback": "resumeGame",
-		"civ": civCode
-	});
+	Engine.PushGuiPage(
+		"page_viewer.xml",
+		{
+			"templateName": templateName,
+			"civ": civCode
+		},
+		resumeGame);
 }
 
 /**
diff --git a/binaries/data/mods/public/gui/session/top_panel/civ_icon.xml b/binaries/data/mods/public/gui/session/top_panel/civ_icon.xml
index 7883610371..784f1b32fa 100644
--- a/binaries/data/mods/public/gui/session/top_panel/civ_icon.xml
+++ b/binaries/data/mods/public/gui/session/top_panel/civ_icon.xml
@@ -6,6 +6,6 @@
 	tooltip_style="sessionToolTipBold"
 >
 	<object name="civIconOverlay" style="CivIconOverlay" size="0 0 100% 100%" type="button">
-		<action on="Press">openStrucTree()</action>
+		<action on="Press">openStrucTree(g_CivInfo.page)</action>
 	</object>
 </object>
diff --git a/binaries/data/mods/public/gui/splashscreen/splashscreen.js b/binaries/data/mods/public/gui/splashscreen/splashscreen.js
index 662dd47823..b26f81b62c 100644
--- a/binaries/data/mods/public/gui/splashscreen/splashscreen.js
+++ b/binaries/data/mods/public/gui/splashscreen/splashscreen.js
@@ -10,5 +10,5 @@ function closePage()
 {
 	Engine.ConfigDB_CreateAndWriteValueToFile("user", "gui.splashscreen.enable", String(Engine.GetGUIObjectByName("displaySplashScreen").checked), "config/user.cfg");
 	Engine.ConfigDB_CreateAndWriteValueToFile("user", "gui.splashscreen.version", Engine.GetFileMTime(g_SplashScreenFile), "config/user.cfg");
-	Engine.PopGuiPageCB();
+	Engine.PopGuiPage();
 }
diff --git a/binaries/data/mods/public/gui/summary/summary.js b/binaries/data/mods/public/gui/summary/summary.js
index 077ce8c078..4a643e6c4d 100644
--- a/binaries/data/mods/public/gui/summary/summary.js
+++ b/binaries/data/mods/public/gui/summary/summary.js
@@ -443,7 +443,7 @@ function continueButton()
 		"charts": g_SelectedChart
 	};
 	if (g_GameData.gui.isInGame)
-		Engine.PopGuiPageCB({
+		Engine.PopGuiPage({
 			"explicitResume": 0,
 			"summarySelectedData": summarySelectedData
 		});
diff --git a/source/gui/GUIManager.cpp b/source/gui/GUIManager.cpp
index 1478d16747..c4ceb6d44a 100644
--- a/source/gui/GUIManager.cpp
+++ b/source/gui/GUIManager.cpp
@@ -89,19 +89,24 @@ void CGUIManager::SwitchPage(const CStrW& pageName, ScriptInterface* srcScriptIn
 
 	m_PageStack.clear();
 
-	PushPage(pageName, initDataClone);
+	PushPage(pageName, initDataClone, JS::UndefinedHandleValue);
 }
 
-void CGUIManager::PushPage(const CStrW& pageName, shared_ptr<ScriptInterface::StructuredClone> initData)
+void CGUIManager::PushPage(const CStrW& pageName, shared_ptr<ScriptInterface::StructuredClone> initData, JS::HandleValue callbackFunction)
 {
+	// Store the callback handler in the current GUI page before opening the new one
+	if (!m_PageStack.empty() && !callbackFunction.isUndefined())
+		m_PageStack.back().SetCallbackFunction(*m_ScriptInterface, callbackFunction);
+
 	// Push the page prior to loading its contents, because that may push
 	// another GUI page on init which should be pushed on top of this new page.
 	m_PageStack.emplace_back(pageName, initData);
 	m_PageStack.back().LoadPage(m_ScriptRuntime);
+
 	ResetCursor();
 }
 
-void CGUIManager::PopPage()
+void CGUIManager::PopPage(shared_ptr<ScriptInterface::StructuredClone> args)
 {
 	if (m_PageStack.size() < 2)
 	{
@@ -110,58 +115,11 @@ void CGUIManager::PopPage()
 	}
 
 	m_PageStack.pop_back();
-}
-
-void CGUIManager::PopPageCB(shared_ptr<ScriptInterface::StructuredClone> args)
-{
-	shared_ptr<ScriptInterface::StructuredClone> initDataClone = m_PageStack.back().initData;
-	PopPage();
-
-	shared_ptr<ScriptInterface> scriptInterface = m_PageStack.back().gui->GetScriptInterface();
-	JSContext* cx = scriptInterface->GetContext();
-	JSAutoRequest rq(cx);
-
-	JS::RootedValue initDataVal(cx);
-	if (!initDataClone)
-	{
-		LOGERROR("Called PopPageCB when initData (which should contain the callback function name) isn't set!");
-		return;
-	}
-
-	scriptInterface->ReadStructuredClone(initDataClone, &initDataVal);
-
-	if (!scriptInterface->HasProperty(initDataVal, "callback"))
-	{
-		LOGERROR("Called PopPageCB when the callback function name isn't set!");
-		return;
-	}
-
-	std::string callback;
-	if (!scriptInterface->GetProperty(initDataVal, "callback", callback))
-	{
-		LOGERROR("Failed to get the callback property as a string from initData in PopPageCB!");
-		return;
-	}
-
-	JS::RootedValue global(cx, scriptInterface->GetGlobalObject());
-	if (!scriptInterface->HasProperty(global, callback.c_str()))
-	{
-		LOGERROR("The specified callback function %s does not exist in the page %s", callback, utf8_from_wstring(m_PageStack.back().name));
-		return;
-	}
-
-	JS::RootedValue argVal(cx);
-	if (args)
-		scriptInterface->ReadStructuredClone(args, &argVal);
-	if (!scriptInterface->CallFunctionVoid(global, callback.c_str(), argVal))
-	{
-		LOGERROR("Failed to call the callback function %s in the page %s", callback, utf8_from_wstring(m_PageStack.back().name));
-		return;
-	}
+	m_PageStack.back().PerformCallbackFunction(args);
 }
 
 CGUIManager::SGUIPage::SGUIPage(const CStrW& pageName, const shared_ptr<ScriptInterface::StructuredClone> initData)
-	: name(pageName), initData(initData), inputs(), gui()
+	: name(pageName), initData(initData), inputs(), gui(), callbackFunction()
 {
 }
 
@@ -256,6 +214,52 @@ void CGUIManager::SGUIPage::LoadPage(shared_ptr<ScriptRuntime> scriptRuntime)
 		LOGERROR("GUI page '%s': Failed to call init() function", utf8_from_wstring(name));
 }
 
+void CGUIManager::SGUIPage::SetCallbackFunction(ScriptInterface& scriptInterface, JS::HandleValue callbackFunc)
+{
+	if (!callbackFunc.isObject())
+	{
+		LOGERROR("Given callback handler is not an object!");
+		return;
+	}
+
+	// Does not require JSAutoRequest
+	if (!JS_ObjectIsFunction(scriptInterface.GetContext(), &callbackFunc.toObject()))
+	{
+		LOGERROR("Given callback handler is not a function!");
+		return;
+	}
+
+	callbackFunction = std::make_shared<JS::PersistentRootedValue>(scriptInterface.GetJSRuntime(), callbackFunc);
+}
+
+void CGUIManager::SGUIPage::PerformCallbackFunction(shared_ptr<ScriptInterface::StructuredClone> args)
+{
+	if (!callbackFunction)
+		return;
+
+	shared_ptr<ScriptInterface> scriptInterface = gui->GetScriptInterface();
+	JSContext* cx = scriptInterface->GetContext();
+	JSAutoRequest rq(cx);
+
+	JS::RootedObject globalObj(cx, &scriptInterface->GetGlobalObject().toObject());
+
+	JS::RootedValue funcVal(cx, *callbackFunction);
+
+	// Delete the callback function, so that it is not called again
+	callbackFunction.reset();
+
+	JS::RootedValue argVal(cx);
+	if (args)
+		scriptInterface->ReadStructuredClone(args, &argVal);
+
+	JS::AutoValueVector paramData(cx);
+	paramData.append(argVal);
+
+	JS::RootedValue result(cx);
+
+	JS_CallFunctionValue(cx, globalObj, funcVal, paramData, &result);
+}
+
 Status CGUIManager::ReloadChangedFile(const VfsPath& path)
 {
 	for (SGUIPage& p : m_PageStack)
diff --git a/source/gui/GUIManager.h b/source/gui/GUIManager.h
index ba76727dc4..615c4e1081 100644
--- a/source/gui/GUIManager.h
+++ b/source/gui/GUIManager.h
@@ -72,15 +72,15 @@ public:
 	 * Load a new GUI page and make it active. All current pages will be retained,
 	 * and will still be drawn and receive tick events, but will not receive
 	 * user inputs.
+	 * If given, the callbackHandler function will be executed once this page is closed.
 	 */
-	void PushPage(const CStrW& pageName, shared_ptr<ScriptInterface::StructuredClone> initData);
+	void PushPage(const CStrW& pageName, shared_ptr<ScriptInterface::StructuredClone> initData, JS::HandleValue callbackFunc);
 
 	/**
 	 * Unload the currently active GUI page, and make the previous page active.
 	 * (There must be at least two pages when you call this.)
 	 */
-	void PopPage();
-	void PopPageCB(shared_ptr<ScriptInterface::StructuredClone> args);
+	void PopPage(shared_ptr<ScriptInterface::StructuredClone> args);
 
 	/**
 	 * Called when a file has been modified, to hotload changes.
@@ -145,13 +145,37 @@ private:
 	{
 		// COPYABLE, because event handlers may invalidate page stack iterators by open or close pages,
 		// and event handlers need to be called for the entire stack.
+
+		/**
+		 * Initializes the data that will be used to create the CGUI page one or multiple times (hotloading).
+		 */
 		SGUIPage(const CStrW& pageName, const shared_ptr<ScriptInterface::StructuredClone> initData);
+
+		/**
+		 * Create the CGUI with it's own ScriptInterface. Deletes the previous CGUI if it existed.
+		 */
 		void LoadPage(shared_ptr<ScriptRuntime> scriptRuntime);
 
+		/**
+		 * Sets the callback handler when a new page is opened that will be performed when the page is closed.
+		 */
+		void SetCallbackFunction(ScriptInterface& scriptInterface, JS::HandleValue callbackFunc);
+
+		/**
+		 * Execute the stored callback function with the given arguments.
+		 */
+		void PerformCallbackFunction(shared_ptr<ScriptInterface::StructuredClone> args);
+
 		CStrW name;
 		boost::unordered_set<VfsPath> inputs; // for hotloading
 		shared_ptr<ScriptInterface::StructuredClone> initData; // data to be passed to the init() function
 		shared_ptr<CGUI> gui; // the actual GUI page
+
+		/**
+		 * Function executed by this parent GUI page when the child GUI page it pushed is popped.
+		 * Notice that storing it in the SGUIPage instead of CGUI means that it will survive the hotloading CGUI reset.
+		 */
+		shared_ptr<JS::PersistentRootedValue> callbackFunction;
 	};
 
 	shared_ptr<CGUI> top() const;
diff --git a/source/gui/scripting/JSInterface_GUIManager.cpp b/source/gui/scripting/JSInterface_GUIManager.cpp
index 33d868559b..89a22e9974 100644
--- a/source/gui/scripting/JSInterface_GUIManager.cpp
+++ b/source/gui/scripting/JSInterface_GUIManager.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2018 Wildfire Games.
+/* Copyright (C) 2019 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -27,9 +27,9 @@
 
 // Note that the initData argument may only contain clonable data.
 // Functions aren't supported for example!
-void JSI_GUIManager::PushGuiPage(ScriptInterface::CxPrivate* pCxPrivate, const std::wstring& name, JS::HandleValue initData)
+void JSI_GUIManager::PushGuiPage(ScriptInterface::CxPrivate* pCxPrivate, const std::wstring& name, JS::HandleValue initData, JS::HandleValue callbackFunction)
 {
-	g_GUI->PushPage(name, pCxPrivate->pScriptInterface->WriteStructuredClone(initData));
+	g_GUI->PushPage(name, pCxPrivate->pScriptInterface->WriteStructuredClone(initData), callbackFunction);
 }
 
 void JSI_GUIManager::SwitchGuiPage(ScriptInterface::CxPrivate* pCxPrivate, const std::wstring& name, JS::HandleValue initData)
@@ -37,14 +37,9 @@ void JSI_GUIManager::SwitchGuiPage(ScriptInterface::CxPrivate* pCxPrivate, const
 	g_GUI->SwitchPage(name, pCxPrivate->pScriptInterface, initData);
 }
 
-void JSI_GUIManager::PopGuiPage(ScriptInterface::CxPrivate* UNUSED(pCxPrivate))
+void JSI_GUIManager::PopGuiPage(ScriptInterface::CxPrivate* pCxPrivate, JS::HandleValue args)
 {
-	g_GUI->PopPage();
-}
-
-void JSI_GUIManager::PopGuiPageCB(ScriptInterface::CxPrivate* pCxPrivate, JS::HandleValue args)
-{
-	g_GUI->PopPageCB(pCxPrivate->pScriptInterface->WriteStructuredClone(args));
+	g_GUI->PopPage(pCxPrivate->pScriptInterface->WriteStructuredClone(args));
 }
 
 JS::Value JSI_GUIManager::GetGUIObjectByName(ScriptInterface::CxPrivate* pCxPrivate, const std::string& name)
@@ -82,10 +77,9 @@ CParamNode JSI_GUIManager::GetTemplate(ScriptInterface::CxPrivate* UNUSED(pCxPri
 
 void JSI_GUIManager::RegisterScriptFunctions(const ScriptInterface& scriptInterface)
 {
-	scriptInterface.RegisterFunction<void, std::wstring, JS::HandleValue, &PushGuiPage>("PushGuiPage");
+	scriptInterface.RegisterFunction<void, std::wstring, JS::HandleValue, JS::HandleValue, &PushGuiPage>("PushGuiPage");
 	scriptInterface.RegisterFunction<void, std::wstring, JS::HandleValue, &SwitchGuiPage>("SwitchGuiPage");
-	scriptInterface.RegisterFunction<void, &PopGuiPage>("PopGuiPage");
-	scriptInterface.RegisterFunction<void, JS::HandleValue, &PopGuiPageCB>("PopGuiPageCB");
+	scriptInterface.RegisterFunction<void, JS::HandleValue, &PopGuiPage>("PopGuiPage");
 	scriptInterface.RegisterFunction<JS::Value, std::string, &GetGUIObjectByName>("GetGUIObjectByName");
 	scriptInterface.RegisterFunction<std::wstring, std::wstring, &SetCursor>("SetCursor");
 	scriptInterface.RegisterFunction<void, &ResetCursor>("ResetCursor");
diff --git a/source/gui/scripting/JSInterface_GUIManager.h b/source/gui/scripting/JSInterface_GUIManager.h
index 0d1119ae8d..b69aae1669 100644
--- a/source/gui/scripting/JSInterface_GUIManager.h
+++ b/source/gui/scripting/JSInterface_GUIManager.h
@@ -23,10 +23,9 @@
 
 namespace JSI_GUIManager
 {
-	void PushGuiPage(ScriptInterface::CxPrivate* pCxPrivate, const std::wstring& name, JS::HandleValue initData);
+	void PushGuiPage(ScriptInterface::CxPrivate* pCxPrivate, const std::wstring& name, JS::HandleValue initData, JS::HandleValue callbackFunction);
 	void SwitchGuiPage(ScriptInterface::CxPrivate* pCxPrivate, const std::wstring& name, JS::HandleValue initData);
-	void PopGuiPage(ScriptInterface::CxPrivate* pCxPrivate);
-	void PopGuiPageCB(ScriptInterface::CxPrivate* pCxPrivate, JS::HandleValue args);
+	void PopGuiPage(ScriptInterface::CxPrivate* pCxPrivate, JS::HandleValue args);
 	JS::Value GetGUIObjectByName(ScriptInterface::CxPrivate* pCxPrivate, const std::string& name);
 	std::wstring SetCursor(ScriptInterface::CxPrivate* pCxPrivate, const std::wstring& name);
 	void ResetCursor(ScriptInterface::CxPrivate* pCxPrivate);