reactive-python · JamesHutchison · Mar 17, 2026 · Mar 17, 2026 · Mar 19, 2026 · Mar 19, 2026
diff --git a/src/build_scripts/install_deps.py b/src/build_scripts/install_deps.py
@@ -30,7 +30,7 @@ def find_deps(data):
 
 
 def install_deps():
-    pyproject_path = Path(__file__).parent.parent / "pyproject.toml"
+    pyproject_path = Path(__file__).parent.parent.parent / "pyproject.toml"
     with open(pyproject_path, "rb") as f:
         pyproject_data = toml.load(f)
     find_deps(pyproject_data)

diff --git a/src/reactpy/executors/asgi/pyscript.py b/src/reactpy/executors/asgi/pyscript.py
@@ -19,6 +19,7 @@
 )
 from reactpy.executors.utils import vdom_head_to_html
 from reactpy.types import ReactPyConfig, VdomDict
+from reactpy.utils import reactpy_to_string
 
 
 class ReactPyCsr(ReactPy):
@@ -32,6 +33,7 @@ def __init__(
         initial: str | VdomDict = "",
         http_headers: dict[str, str] | None = None,
         html_head: VdomDict | None = None,
+        prepend_body: VdomDict | None = ...,  # type: ignore[assignment]
         html_lang: str = "en",
         **settings: Unpack[ReactPyConfig],
     ) -> None:
@@ -59,6 +61,9 @@ def __init__(
                 commonly used to render a loading animation.
             http_headers: Additional headers to include in the HTTP response for the base HTML document.
             html_head: Additional head elements to include in the HTML response.
+            prepend_body: Content rendered at the start of the ``<body>`` element.
+                A ``VdomDict`` constructed via ``html.*`` functions, or ``None`` to omit.
+                Defaults to ``html.noscript("Enable JavaScript to view this site.")``.
             html_lang: The language of the HTML document.
             settings:
                 Global ReactPy configuration settings that affect behavior and performance. Most settings
@@ -78,6 +83,10 @@ def __init__(
         self.extra_headers = http_headers or {}
         self.dispatcher_pattern = re.compile(f"^{self.dispatcher_path}?")
         self.html_head = html_head or html.head()
+        if prepend_body is not ...:
+            self.prepend_body = prepend_body
+        else:
+            self.prepend_body = html.noscript("Enable JavaScript to view this site.")
         self.html_lang = html_lang
 
     def match_dispatch_path(self, scope: AsgiWebsocketScope) -> bool:  # nocov
@@ -97,6 +106,11 @@ class ReactPyPyscriptApp(ReactPyApp):
     def render_index_html(self) -> None:
         """Process the index.html and store the results in this class."""
         head_content = vdom_head_to_html(self.parent.html_head)
+        body_content = (
+            ""
+            if self.parent.prepend_body is None
+            else reactpy_to_string(self.parent.prepend_body)
+        )
         pyscript_setup = pyscript_setup_html(
             extra_py=self.parent.extra_py,
             extra_js=self.parent.extra_js,
@@ -114,6 +128,7 @@ def render_index_html(self) -> None:
             f'<html lang="{self.parent.html_lang}">'
             f"{head_content}"
             "<body>"
+            f"{body_content}"
             f"{pyscript_component}"
             "</body>"
             "</html>"

diff --git a/src/reactpy/executors/asgi/standalone.py b/src/reactpy/executors/asgi/standalone.py
@@ -24,14 +24,17 @@
     AsgiWebsocketScope,
 )
 from reactpy.executors.pyscript.utils import pyscript_setup_html
-from reactpy.executors.utils import server_side_component_html, vdom_head_to_html
+from reactpy.executors.utils import (
+    server_side_component_html,
+    vdom_head_to_html,
+)
 from reactpy.types import (
     PyScriptOptions,
     ReactPyConfig,
     RootComponentConstructor,
     VdomDict,
 )
-from reactpy.utils import import_dotted_path, string_to_reactpy
+from reactpy.utils import import_dotted_path, reactpy_to_string, string_to_reactpy
 
 _logger = getLogger(__name__)
 
@@ -45,6 +48,7 @@ def __init__(
         *,
         http_headers: dict[str, str] | None = None,
         html_head: VdomDict | None = None,
+        prepend_body: VdomDict | None = ...,  # type: ignore[assignment]
         html_lang: str = "en",
         pyscript_setup: bool = False,
         pyscript_options: PyScriptOptions | None = None,
@@ -56,6 +60,9 @@ def __init__(
             root_component: The root component to render. This app is typically a single page application.
             http_headers: Additional headers to include in the HTTP response for the base HTML document.
             html_head: Additional head elements to include in the HTML response.
+            prepend_body: Content rendered at the start of the ``<body>`` element.
+                A ``VdomDict`` constructed via ``html.*`` functions, or ``None`` to omit.
+                Defaults to ``html.noscript("Enable JavaScript to view this site.")``.
             html_lang: The language of the HTML document.
             pyscript_setup: Whether to automatically load PyScript within your HTML head.
             pyscript_options: Options to configure PyScript behavior.
@@ -66,6 +73,10 @@ def __init__(
         self.extra_headers = http_headers or {}
         self.dispatcher_pattern = re.compile(f"^{self.dispatcher_path}?")
         self.html_head = html_head or html.head()
+        if prepend_body is not ...:
+            self.prepend_body = prepend_body
+        else:
+            self.prepend_body = html.noscript("Enable JavaScript to view this site.")
         self.html_lang = html_lang
 
         if pyscript_setup:
@@ -229,11 +240,17 @@ async def __call__(
 
     def render_index_html(self) -> None:
         """Process the index.html and store the results in this class."""
+        body_content = (
+            ""
+            if self.parent.prepend_body is None
+            else reactpy_to_string(self.parent.prepend_body)
+        )
         self._index_html = (
             "<!doctype html>"
             f'<html lang="{self.parent.html_lang}">'
             f"{vdom_head_to_html(self.parent.html_head)}"
             "<body>"
+            f"{body_content}"
             f"{server_side_component_html(element_id='app', class_='', component_path='')}"
             "</body>"
             "</html>"

diff --git a/tests/test_asgi/test_pyscript.py b/tests/test_asgi/test_pyscript.py
@@ -1,17 +1,22 @@
 # ruff: noqa: S701
+import asyncio
 from pathlib import Path
 
 import pytest
 from jinja2 import Environment as JinjaEnvironment
 from jinja2 import FileSystemLoader as JinjaFileSystemLoader
+from requests import request
 from starlette.applications import Starlette
 from starlette.routing import Route
 from starlette.templating import Jinja2Templates
 
+from reactpy import config as _config
 from reactpy import html
 from reactpy.executors.asgi.pyscript import ReactPyCsr
 from reactpy.testing import BackendFixture, DisplayFixture
 
+REACTPY_TESTS_DEFAULT_TIMEOUT = _config.REACTPY_TESTS_DEFAULT_TIMEOUT
+
 
 @pytest.fixture(scope="module")
 async def display(browser):
@@ -102,6 +107,66 @@ def test_bad_file_path():
         ReactPyCsr()
 
 
+async def test_customized_noscript_vdom():
+    app = ReactPyCsr(
+        Path(__file__).parent / "pyscript_components" / "root.py",
+        prepend_body=html.noscript(
+            html.p({"id": "noscript-message"}, "Please enable JavaScript.")
+        ),
+    )
+
+    async with BackendFixture(app) as server:
+        url = f"http://{server.host}:{server.port}"
+        response = await asyncio.to_thread(
+            request, "GET", url, timeout=REACTPY_TESTS_DEFAULT_TIMEOUT.current
+        )
+        assert response.status_code == 200
+        assert (
+            '<noscript><p id="noscript-message">Please enable JavaScript.</p></noscript>'
+            in response.text
+        )
+
+    async with BackendFixture(app) as server:
+        url = f"http://{server.host}:{server.port}"
+        response = await asyncio.to_thread(
+            request, "GET", url, timeout=REACTPY_TESTS_DEFAULT_TIMEOUT.current
+        )
+        assert response.status_code == 200
+        assert (
+            '<noscript><p id="noscript-message">Please enable JavaScript.</p></noscript>'
+            in response.text
+        )
+
+
+async def test_prepend_body_default_is_noscript():
+    app = ReactPyCsr(Path(__file__).parent / "pyscript_components" / "root.py")
+
+    async with BackendFixture(app) as server:
+        url = f"http://{server.host}:{server.port}"
+        response = await asyncio.to_thread(
+            request, "GET", url, timeout=REACTPY_TESTS_DEFAULT_TIMEOUT.current
+        )
+        assert response.status_code == 200
+        assert (
+            "<noscript>Enable JavaScript to view this site.</noscript>" in response.text
+        )
+
+
+async def test_prepend_body_disabled():
+    app = ReactPyCsr(
+        Path(__file__).parent / "pyscript_components" / "root.py",
+        prepend_body=None,
+    )
+
+    async with BackendFixture(app) as server:
+        url = f"http://{server.host}:{server.port}"
+        response = await asyncio.to_thread(
+            request, "GET", url, timeout=REACTPY_TESTS_DEFAULT_TIMEOUT.current
+        )
+        assert response.status_code == 200
+        assert "<noscript>" not in response.text
+
+
 async def test_jinja_template_tag(jinja_display: DisplayFixture):
     await jinja_display.goto("/")
 

diff --git a/tests/test_asgi/test_standalone.py b/tests/test_asgi/test_standalone.py
@@ -193,6 +193,64 @@ def sample():
             assert (await new_display.page.title()) == custom_title
 
 
+async def test_prepend_body_vdom():
+    @reactpy.component
+    def sample():
+        return html.h1("Hello World")
+
+    app = ReactPy(
+        sample,
+        prepend_body=html.noscript(
+            html.p({"id": "noscript-message"}, "Please enable JavaScript.")
+        ),
+    )
+
+    async with BackendFixture(app) as server:
+        url = f"http://{server.host}:{server.port}"
+        response = await asyncio.to_thread(
+            request, "GET", url, timeout=REACTPY_TESTS_DEFAULT_TIMEOUT.current
+        )
+        assert response.status_code == 200
+        assert (
+            '<noscript><p id="noscript-message">Please enable JavaScript.</p></noscript>'
+            in response.text
+        )
+
+
+async def test_prepend_body_default_is_noscript():
+    @reactpy.component
+    def sample():
+        return html.h1("Hello World")
+
+    app = ReactPy(sample)
+
+    async with BackendFixture(app) as server:
+        url = f"http://{server.host}:{server.port}"
+        response = await asyncio.to_thread(
+            request, "GET", url, timeout=REACTPY_TESTS_DEFAULT_TIMEOUT.current
+        )
+        assert response.status_code == 200
+        assert (
+            "<noscript>Enable JavaScript to view this site.</noscript>" in response.text
+        )
+
+
+async def test_prepend_body_disabled():
+    @reactpy.component
+    def sample():
+        return html.h1("Hello World")
+
+    app = ReactPy(sample, prepend_body=None)
+
+    async with BackendFixture(app) as server:
+        url = f"http://{server.host}:{server.port}"
+        response = await asyncio.to_thread(
+            request, "GET", url, timeout=REACTPY_TESTS_DEFAULT_TIMEOUT.current
+        )
+        assert response.status_code == 200
+        assert "<noscript>" not in response.text
+
+
 async def test_head_request():
     @reactpy.component
     def sample():

diff --git a/tests/test_asgi/test_utils.py b/tests/test_asgi/test_utils.py
@@ -1,6 +1,6 @@
 import pytest
 
-from reactpy import config
+from reactpy import config, html
 from reactpy.executors import utils
 
 
@@ -9,6 +9,26 @@ def test_invalid_vdom_head():
         utils.vdom_head_to_html({"tagName": "invalid"})
 
 
+def test_prepend_body_content_as_vdom_dict():
+    from reactpy.utils import reactpy_to_string
+
+    assert (
+        reactpy_to_string(
+            html.div(html.p({"id": "noscript-message"}, "Please enable JavaScript."))
+        )
+        == '<div><p id="noscript-message">Please enable JavaScript.</p></div>'
+    )
+
+
+def test_prepend_body_content_as_noscript():
+    from reactpy.utils import reactpy_to_string
+
+    assert (
+        reactpy_to_string(html.noscript(html.p("Enable JavaScript to view this site.")))
+        == "<noscript><p>Enable JavaScript to view this site.</p></noscript>"
+    )
+
+
 def test_process_settings():
     utils.process_settings({"async_rendering": False})
     assert config.REACTPY_ASYNC_RENDERING.current is False