Concepts
HTML in Markdown
Understand raw HTML blocks and inline HTML embedded in Markdown documents.
CommonMark defines raw HTML blocks and inline raw HTML inside Markdown. This makes it possible to express structures that Markdown syntax does not provide directly.
Raw HTML is not handled identically by every renderer. A publishing system may preserve it, interpret it, escape it, or remove it through sanitization. Avoid assuming that embedded HTML will behave the same in source editors, static-site generators, document converters, and untrusted-content pipelines.
When portability matters, test the document with each intended Markdown host and treat active or untrusted HTML as a security boundary.