Hi, and thank you so much for MyST-NB — it's been wonderful to work with, and the executable-docs workflow is exactly what we were hoping for. 🙏
I have a small feature request, and I fully apologise if I've simply missed an existing option or am misunderstanding something — please point me at the docs if so.
Summary
Would the maintainers consider (optionally) honoring the isolated output metadata when rendering text/html outputs in the static HTML build — i.e. emitting the output inside a sandboxed iframe (e.g. <iframe srcdoc="…">) rather than inlining it?
Background / current behavior
Some libraries' rich reprs return a full, standalone HTML document (<!DOCTYPE html><html>…</html>) and signal — via the isolated output metadata — that it should be rendered in isolation. The live Jupyter Notebook frontends honor this by sandboxing the output in an iframe, so the full document renders correctly.
When the same notebook is built with MyST-NB, the text/html output appears to be inlined regardless of the isolated flag. For a full-document repr this produces a nested <!DOCTYPE html>/<html> inside the page <body>, which is invalid HTML and doesn't render reliably.
Minimal reproducible example
conf.py:
extensions = ["myst_nb"]
nb_execution_mode = "force"
index.md:
---
file_format: mystnb
kernelspec:
name: python3
display_name: Python 3
---
# Isolated HTML output demo
```{code-cell} python
class FullDocViewer:
"""A rich repr that returns a *full* standalone HTML document and asks,
via the `isolated` metadata, for it to be rendered in isolation."""
def _repr_mimebundle_(self, include=None, exclude=None):
html = (
"<!DOCTYPE html><html><head><meta charset='utf-8'><title>demo</title>"
"<style>body { background: #eef; }</style></head>"
"<body><h1>Hello from an isolated document</h1></body></html>"
)
return {"text/html": html}, {"text/html": {"isolated": True}}
FullDocViewer()
```Build:
sphinx-build -b html . _build/html
Observed: _build/html/index.html contains the full document inlined — there are two <!DOCTYPE html> in one page, and the isolated flag is ignored.
Hoped-for: the output is rendered in a sandboxed iframe (e.g. <iframe srcdoc="…">), matching how the classic Notebook frontend treats isolated outputs, so full-document HTML reprs display correctly in the built docs.
Possible approaches (just ideas — you'll know far better)
- Honor
{"text/html": {"isolated": true}} (or the top-level isolated metadata) by wrapping the HTML in an <iframe srcdoc="…">; or
- A config flag (e.g.
nb_render_html_isolated = True) for projects that want this opt-in.
Related issues (not duplicates)
#54 and #436 cover interactive fragments (Plotly/Bokeh/HoloViews emit <div> + <script> that inline fine once JS loading is handled). This request is specifically about outputs that are a full standalone HTML document and rely on the isolated convention — a different case that iframe-sandboxing would solve.
Why it matters to us
We maintain a small simulation library whose interactive viewer is a self-contained HTML document; it renders perfectly in Jupyter but we can't currently embed it in our MyST-NB docs without falling back to manually generating files and hand-writing iframes.
Environment
- myst-nb 1.4.0 (latest)
- sphinx 9.1.0
- myst-parser 5.1.0
- nbclient 0.10.4
- docutils 0.22.4
- Python 3.13.3
I completely understand if this is out of scope or intentionally left to the frontend — and I'm very happy to attempt a PR with a little guidance if you'd welcome one. Thank you again for the project and for considering this. 🙏
Hi, and thank you so much for MyST-NB — it's been wonderful to work with, and the executable-docs workflow is exactly what we were hoping for. 🙏
I have a small feature request, and I fully apologise if I've simply missed an existing option or am misunderstanding something — please point me at the docs if so.
Summary
Would the maintainers consider (optionally) honoring the
isolatedoutput metadata when renderingtext/htmloutputs in the static HTML build — i.e. emitting the output inside a sandboxed iframe (e.g.<iframe srcdoc="…">) rather than inlining it?Background / current behavior
Some libraries' rich reprs return a full, standalone HTML document (
<!DOCTYPE html><html>…</html>) and signal — via theisolatedoutput metadata — that it should be rendered in isolation. The live Jupyter Notebook frontends honor this by sandboxing the output in an iframe, so the full document renders correctly.When the same notebook is built with MyST-NB, the
text/htmloutput appears to be inlined regardless of theisolatedflag. For a full-document repr this produces a nested<!DOCTYPE html>/<html>inside the page<body>, which is invalid HTML and doesn't render reliably.Minimal reproducible example
conf.py:index.md:Build:
sphinx-build -b html . _build/htmlObserved:
_build/html/index.htmlcontains the full document inlined — there are two<!DOCTYPE html>in one page, and theisolatedflag is ignored.Hoped-for: the output is rendered in a sandboxed iframe (e.g.
<iframe srcdoc="…">), matching how the classic Notebook frontend treatsisolatedoutputs, so full-document HTML reprs display correctly in the built docs.Possible approaches (just ideas — you'll know far better)
{"text/html": {"isolated": true}}(or the top-levelisolatedmetadata) by wrapping the HTML in an<iframe srcdoc="…">; ornb_render_html_isolated = True) for projects that want this opt-in.Related issues (not duplicates)
#54 and #436 cover interactive fragments (Plotly/Bokeh/HoloViews emit
<div>+<script>that inline fine once JS loading is handled). This request is specifically about outputs that are a full standalone HTML document and rely on theisolatedconvention — a different case that iframe-sandboxing would solve.Why it matters to us
We maintain a small simulation library whose interactive viewer is a self-contained HTML document; it renders perfectly in Jupyter but we can't currently embed it in our MyST-NB docs without falling back to manually generating files and hand-writing iframes.
Environment
I completely understand if this is out of scope or intentionally left to the frontend — and I'm very happy to attempt a PR with a little guidance if you'd welcome one. Thank you again for the project and for considering this. 🙏