Why is it only HTML that can be run offline?

Question

I wonder what makes HTML special so it can be run offline... why SL dont make it for others...

Answer 1

HTML doesn't require compiler or interpreter.
The source code is not sent to the server because your browser is capable of translating web languages on its own.

Answer 2

// Hi Undefined,
Because HTML is a markup language and Sololearn has saved your codes only your HTML codes.