Logic is also logic, so most texts (your comment excepted) shouldn't be allowed in markup. Note that nobody actually wants to embed the code for validation wit

Logic is also logic, so most texts (your comment excepted) shouldn't be allowed in markup. Note that nobody actually wants to embed the code for validation within the document, but you want to be able to properly identify a form-elements attributes so as to allow clients to make a smart choice about validation, presentation, defaults etc. JPEG decoding is also logic, but it's also pretty useful for client to know that the binary stream it's reading may best be handled with the jpeg library.