.. _doc_exporting_for_web: Exporting for the Web ===================== .. seealso:: This page describes how to export a Godot project to HTML5. If you're looking to compile editor or export template binaries from source instead, read :ref:`doc_compiling_for_web`. HTML5 export allows publishing games made in Godot Engine to the browser. This requires support for `WebAssembly `__, `WebGL `__ and `SharedArrayBuffer `_ in the user's browser. .. attention:: Projects written in C# using Godot 4 currently cannot be exported to the web. To use C# on web platforms, use Godot 3 instead. .. tip:: Use the browser-integrated developer console, usually opened with :kbd:`F12` (:kbd:`Cmd + Option + I` on macOS), to view **debug information** like JavaScript, engine, and WebGL errors. .. attention:: Godot 4's HTML5 exports currently cannot run on macOS and iOS due to upstream bugs with SharedArrayBuffer and WebGL 2.0. We recommend using :ref:`macOS ` and :ref:`iOS ` native export functionality instead, as it will also result in better performance. Godot 3's HTML5 exports are more compatible with various browsers in general, especially when using the GLES2 rendering backend (which only requires WebGL 1.0). WebGL version ------------- Godot 4.0 and later can only target WebGL 2.0 (using the Compatibility rendering method). There is no stable way to run Vulkan applications on the web yet. See `Can I use WebGL 2.0 `__ for a list of browser versions supporting WebGL 2.0. Note that Safari has several issues with WebGL 2.0 support that other browsers don't have, so we recommend using a Chromium-based browser or Firefox if possible. .. _doc_javascript_export_options: Export options -------------- If a runnable web export template is available, a button appears between the *Stop scene* and *Play edited Scene* buttons in the editor to quickly open the game in the default browser for testing. If you plan to use :ref:`VRAM compression ` make sure that **Vram Texture Compression** is enabled for the targeted platforms (enabling both **For Desktop** and **For Mobile** will result in a bigger, but more compatible export). If a path to a **Custom HTML shell** file is given, it will be used instead of the default HTML page. See :ref:`doc_customizing_html5_shell`. **Head Include** is appended into the ```` element of the generated HTML page. This allows to, for example, load webfonts and third-party JavaScript APIs, include CSS, or run JavaScript code. .. important:: Each project must generate their own HTML file. On export, several text placeholders are replaced in the generated HTML file specifically for the given export options. Any direct modifications to that HTML file will be lost in future exports. To customize the generated file, use the **Custom HTML shell** option. Limitations ----------- For security and privacy reasons, many features that work effortlessly on native platforms are more complicated on the web platform. Following is a list of limitations you should be aware of when porting a Godot game to the web. .. _doc_javascript_secure_contexts: .. important:: Browser vendors are making more and more functionalities only available in `secure contexts `_, this means that such features are only be available if the web page is served via a secure HTTPS connection (localhost is usually exempt from such requirement). Using cookies for data persistence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Users must **allow cookies** (specifically IndexedDB) if persistence of the ``user://`` file system is desired. When playing a game presented in an ``iframe``, **third-party** cookies must also be enabled. Incognito/private browsing mode also prevents persistence. The method ``OS.is_userfs_persistent()`` can be used to check if the ``user://`` file system is persistent, but can give false positives in some cases. Background processing ~~~~~~~~~~~~~~~~~~~~~ The project will be paused by the browser when the tab is no longer the active tab in the user's browser. This means functions such as ``_process()`` and ``_physics_process()`` will no longer run until the tab is made active again by the user (by switching back to the tab). This can cause networked games to disconnect if the user switches tabs for a long duration. This limitation does not apply to unfocused browser *windows*. Therefore, on the user's side, this can be worked around by running the project in a separate *window* instead of a separate tab. Full screen and mouse capture ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Browsers do not allow arbitrarily **entering full screen**. The same goes for **capturing the cursor**. Instead, these actions have to occur as a response to a JavaScript input event. In Godot, this means entering full screen from within a pressed input event callback such as ``_input`` or ``_unhandled_input``. Querying the :ref:`class_Input` singleton is not sufficient, the relevant input event must currently be active. For the same reason, the full screen project setting doesn't work unless the engine is started from within a valid input event handler. This requires :ref:`customization of the HTML page `. Audio ~~~~~ Some browsers restrict autoplay for audio on websites. The easiest way around this limitation is to request the player to click, tap or press a key/button to enable audio, for instance when displaying a splash screen at the start of your game. .. seealso:: Google offers additional information about their `Web Audio autoplay policies `__. Apple's Safari team also posted additional information about their `Auto-Play Policy Changes for macOS `__. .. warning:: Access to microphone requires a :ref:`secure context `. Networking ~~~~~~~~~~ Low level networking is not implemented due to lacking support in browsers. Currently, only :ref:`HTTP client `, :ref:`HTTP requests `, :ref:`WebSocket (client) ` and :ref:`WebRTC ` are supported. The HTTP classes also have several restrictions on the HTML5 platform: - Accessing or changing the ``StreamPeer`` is not possible - Threaded/Blocking mode is not available - Cannot progress more than once per frame, so polling in a loop will freeze - No chunked responses - Host verification cannot be disabled - Subject to `same-origin policy `__ Clipboard ~~~~~~~~~ Clipboard synchronization between engine and the operating system requires a browser supporting the `Clipboard API `__, additionally, due to the API asynchronous nature might not be reliable when accessed from GDScript. .. warning:: Requires a :ref:`secure context `. Gamepads ~~~~~~~~ Gamepads will not be detected until one of their button is pressed. Gamepads might have the wrong mapping depending on the browser/OS/gamepad combination, sadly the `Gamepad API `__ does not provide a reliable way to detect the gamepad information necessary to remap them based on model/vendor/OS due to privacy considerations. .. warning:: Requires a :ref:`secure context `. Boot splash is not displayed ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The default HTML page does not display the boot splash while loading. However, the image is exported as a PNG file, so :ref:`custom HTML pages ` can display it. .. _doc_exporting_for_web_serving_the_files: Serving the files ----------------- Exporting for the web generates several files to be served from a web server, including a default HTML page for presentation. A custom HTML file can be used, see :ref:`doc_customizing_html5_shell`. .. warning:: To ensure low audio latency and the ability to use :ref:`class_Thread` in web exports, Godot 4 web exports always use `SharedArrayBuffer `__. This requires a :ref:`secure context `, while also requiring the following CORS headers to be set when serving the files: :: Cross-Origin-Opener-Policy: same-origin Cross-Origin-Embedder-Policy: require-corp If you don't control the web server or are unable to add response headers, use `coi-serviceworker `__ as a workaround. If the client doesn't receive the required response headers, **the project will not run**. The generated ``.html`` file can be used as ``DirectoryIndex`` in Apache servers and can be renamed to e.g. ``index.html`` at any time. Its name is never depended on by default. The HTML page draws the game at maximum size within the browser window. This way, it can be inserted into an ``