After reading this fragment:
"The willValidate, validity, and validationMessage IDL attributes, and the checkValidity() and setCustomValidity() methods, are part of the constraint validation API. The labels IDL attribute provides a list of the element's labels. The select(), selectionStart, selectionEnd, selectionDirection, setRangeText(), and setSelectionRange() methods and IDL attributes expose the element's text selection. The autofocus, disabled, form, and name IDL attributes are part of the element's forms API."
I think that it can be quite useful to add condition or submit-if attribute to input and select elements with following semantics:
1) if the condition or submit-if attribute has any value and its value is an id of an existing check box or radio input, then the behavior of input or select is same as described in other paragraphs of this document.

1.2) if the condition or submit-if attribute is specified and if no input found by condition value, or a checkbox or radio found, but it is not checked 
the behavior and appearance of this input or select element is same as it has disabled attribute set and its value is not submitted among the form data;

2) if this attribute not set, or no input like check box or radio button with specified id was found, the behavior of this input or select element is usual, as described in other paragraphs of this document.