8 files changed, 52 insertions, 29 deletions
diff --git a/platform/javascript/README.md b/platform/javascript/README.md
index f181bea9e0..812ab6778b 100644
--- a/platform/javascript/README.md
+++ b/platform/javascript/README.md
@@ -5,8 +5,15 @@ compiled using [Emscripten](https://emscripten.org/).
 
 It also contains a ESLint linting setup (see [`package.json`](package.json)).
 
-See also [`misc/dist/html`](/misc/dist/html) folder for files used by this platform
-such as the HTML5 shell.
+See also [`misc/dist/html`](/misc/dist/html) folder for additional files used by
+this platform such as the HTML5 shell.
+
+## Documentation
+
+- [Compiling for the Web](https://docs.godotengine.org/en/latest/development/compiling/compiling_for_web.html)
+  - Instructions on building this platform port from source.
+- [Exporting for the Web](https://docs.godotengine.org/en/latest/tutorials/export/exporting_for_web.html)
+  - Instructions on using the compiled export templates to export a project.
 
 ## Artwork license
 
diff --git a/platform/javascript/detect.py b/platform/javascript/detect.py
index a769260f01..048c9c2eb4 100644
--- a/platform/javascript/detect.py
+++ b/platform/javascript/detect.py
@@ -46,6 +46,7 @@ def get_opts():
 
 def get_flags():
     return [
+        ("arch", "wasm32"),
         ("tools", False),
         ("builtin_pcre2_with_jit", False),
         ("vulkan", False),
@@ -53,6 +54,15 @@ def get_flags():
 
 
 def configure(env):
+    # Validate arch.
+    supported_arches = ["wasm32"]
+    if env["arch"] not in supported_arches:
+        print(
+            'Unsupported CPU architecture "%s" for iOS. Supported architectures are: %s.'
+            % (env["arch"], ", ".join(supported_arches))
+        )
+        sys.exit()
+
     try:
         env["initial_memory"] = int(env["initial_memory"])
     except Exception:
diff --git a/platform/javascript/display_server_javascript.cpp b/platform/javascript/display_server_javascript.cpp
index 48f637fcfe..30240ad2db 100644
--- a/platform/javascript/display_server_javascript.cpp
+++ b/platform/javascript/display_server_javascript.cpp
@@ -296,7 +296,7 @@ void DisplayServerJavaScript::update_voices_callback(int p_size, const char **p_
 	}
 }
 
-Array DisplayServerJavaScript::tts_get_voices() const {
+TypedArray<Dictionary> DisplayServerJavaScript::tts_get_voices() const {
 	godot_js_tts_get_voices(update_voices_callback);
 	return voices;
 }
diff --git a/platform/javascript/display_server_javascript.h b/platform/javascript/display_server_javascript.h
index fb7f5d02a8..cbb91477b7 100644
--- a/platform/javascript/display_server_javascript.h
+++ b/platform/javascript/display_server_javascript.h
@@ -124,7 +124,7 @@ public:
 	// tts
 	virtual bool tts_is_speaking() const override;
 	virtual bool tts_is_paused() const override;
-	virtual Array tts_get_voices() const override;
+	virtual TypedArray<Dictionary> tts_get_voices() const override;
 
 	virtual void tts_speak(const String &p_text, const String &p_voice, int p_volume = 50, float p_pitch = 1.f, float p_rate = 1.f, int p_utterance_id = 0, bool p_interrupt = false) override;
 	virtual void tts_pause() override;
diff --git a/platform/javascript/export/export_plugin.cpp b/platform/javascript/export/export_plugin.cpp
index b99f88d067..0bdee11018 100644
--- a/platform/javascript/export/export_plugin.cpp
+++ b/platform/javascript/export/export_plugin.cpp
@@ -362,7 +362,7 @@ Ref<Texture2D> EditorExportPlatformJavaScript::get_logo() const {
 	return logo;
 }
 
-bool EditorExportPlatformJavaScript::can_export(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const {
+bool EditorExportPlatformJavaScript::has_valid_export_configuration(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const {
 #ifndef DEV_ENABLED
 	// We don't provide export templates for the HTML5 platform currently as there
 	// is no suitable renderer to use with them. So we forbid exporting and tell
@@ -396,7 +396,27 @@ bool EditorExportPlatformJavaScript::can_export(const Ref<EditorExportPreset> &p
 	valid = dvalid || rvalid;
 	r_missing_templates = !valid;
 
-	// Validate the rest of the configuration.
+	if (!err.is_empty()) {
+		r_error = err;
+	}
+
+	return valid;
+}
+
+bool EditorExportPlatformJavaScript::has_valid_project_configuration(const Ref<EditorExportPreset> &p_preset, String &r_error) const {
+#ifndef DEV_ENABLED
+	// We don't provide export templates for the HTML5 platform currently as there
+	// is no suitable renderer to use with them. So we forbid exporting and tell
+	// users why. This is skipped in DEV_ENABLED so that contributors can still test
+	// the pipeline once we start having WebGL or WebGPU support.
+	r_error = "The HTML5 platform is currently not supported in Godot 4.0, as there is no suitable renderer for it.\n";
+	return false;
+#endif
+
+	String err;
+	bool valid = true;
+
+	// Validate the project configuration.
 
 	if (p_preset->get("vram_texture_compression/for_mobile")) {
 		String etc_error = test_etc2();
diff --git a/platform/javascript/export/export_plugin.h b/platform/javascript/export/export_plugin.h
index fbaa3615cb..16bab02d54 100644
--- a/platform/javascript/export/export_plugin.h
+++ b/platform/javascript/export/export_plugin.h
@@ -118,7 +118,8 @@ public:
 	virtual String get_os_name() const override;
 	virtual Ref<Texture2D> get_logo() const override;
 
-	virtual bool can_export(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const override;
+	virtual bool has_valid_export_configuration(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const override;
+	virtual bool has_valid_project_configuration(const Ref<EditorExportPreset> &p_preset, String &r_error) const override;
 	virtual List<String> get_binary_extensions(const Ref<EditorExportPreset> &p_preset) const override;
 	virtual Error export_project(const Ref<EditorExportPreset> &p_preset, bool p_debug, const String &p_path, int p_flags = 0) override;
 
diff --git a/platform/javascript/js/libs/library_godot_display.js b/platform/javascript/js/libs/library_godot_display.js
index c7729a8c5b..768eaf9e1d 100644
--- a/platform/javascript/js/libs/library_godot_display.js
+++ b/platform/javascript/js/libs/library_godot_display.js
@@ -336,26 +336,12 @@ const GodotDisplay = {
 	$GodotDisplay__deps: ['$GodotConfig', '$GodotRuntime', '$GodotDisplayCursor', '$GodotEventListeners', '$GodotDisplayScreen', '$GodotDisplayVK'],
 	$GodotDisplay: {
 		window_icon: '',
-		findDPI: function () {
-			function testDPI(dpi) {
-				return window.matchMedia(`(max-resolution: ${dpi}dpi)`).matches;
-			}
-			function bisect(low, high, func) {
-				const mid = parseInt(((high - low) / 2) + low, 10);
-				if (high - low <= 1) {
-					return func(high) ? high : low;
-				}
-				if (func(mid)) {
-					return bisect(low, mid, func);
-				}
-				return bisect(mid, high, func);
-			}
-			try {
-				const dpi = bisect(0, 800, testDPI);
-				return dpi >= 96 ? dpi : 96;
-			} catch (e) {
-				return 96;
-			}
+		getDPI: function () {
+			// devicePixelRatio is given in dppx
+			// https://drafts.csswg.org/css-values/#resolution
+			// > due to the 1:96 fixed ratio of CSS *in* to CSS *px*, 1dppx is equivalent to 96dpi.
+			const dpi = Math.round(window.devicePixelRatio * 96);
+			return dpi >= 96 ? dpi : 96;
 		},
 	},
 
@@ -461,7 +447,7 @@ const GodotDisplay = {
 
 	godot_js_display_screen_dpi_get__sig: 'i',
 	godot_js_display_screen_dpi_get: function () {
-		return GodotDisplay.findDPI();
+		return GodotDisplay.getDPI();
 	},
 
 	godot_js_display_pixel_ratio_get__sig: 'f',
diff --git a/platform/javascript/os_javascript.h b/platform/javascript/os_javascript.h
index 35e13c94fc..d932745177 100644
--- a/platform/javascript/os_javascript.h
+++ b/platform/javascript/os_javascript.h
@@ -98,7 +98,6 @@ public:
 	String get_user_data_dir() const override;
 
 	bool is_userfs_persistent() const override;
-	bool is_single_window() const override { return true; }
 
 	void alert(const String &p_alert, const String &p_title = "ALERT!") override;