Why is an input tag not allowed directly within a form tag?

Question

I just read the following at http://w3fools.com/#html_forms:

Non-block-level elements (such as ) are not valid directly insi

Answer 1

Well, according to the HTML 4.01 specification (specifically section 17.3), this is technically true. However, I don't know of any web browser that would actually give you a problem over it.