to Self Contained HTML
Returns a complete HTML document for the plot that carries its own copy of the Lets-Plot JS library, so it renders wherever it is put without the surrounding page doing anything.
Differs from toHTML only in that the plot is not wrapped in an iframe. Prefer toEmbeddedHTML for anything being composited into a larger page: a document nested inside another document is invalid, and though browsers recover from it, other tools that consume HTML need not.