I want native Markdown support in textarea elements

I want browsers to provide native Markdown rendering and editing support inside <textarea> elements, so that authors can offer rich-text editing experiences without shipping a full JavaScript WYSIWYG editor and its associated resources.

Today, any website that wants a user-friendly rich-text input field must bundle a third-party editor library — complete with JavaScript bundles, CSS stylesheets, icon sets, and accessibility scaffolding. This overhead is unnecessary in many common cases where the only output format required is Markdown, as standardized in RFC 7763 (text/markdown) and RFC 7764.

A browser-native Markdown <textarea> could work similarly to <input type="date"> or <input type="color">: the browser renders a polished, accessible UI while the underlying form value remains plain Markdown text, which is what gets transmitted to the server.

Key benefits of this approach include:

• Reduced page weight: no need to load a JavaScript editor library and related assets.
• Soft-keyboard optimization: mobile browsers could surface contextual formatting shortcuts (e.g., **, _, #) directly on the keyboard when a Markdown textarea is focused.
• Consistent accessibility: a browser-native implementation would inherit the platform's accessibility infrastructure automatically.
• Standardized output: the submitted value would be valid text/markdown per RFC 7763, making server-side handling predictable.

A limited variant of this feature could also apply to <input type="text"> for single-line inline formatting.

This could be introduced via a new type or format attribute, for example <textarea type="markdown">, keeping the API familiar and the behavior opt-in.