org.danielnixon.saferdom.implicits.html
The form that this element is associated with.
The form that this element is associated with. If this element is a descendant of a form element, then this attribute is the ID of that form element. If the element is not a descendant of a form element, then: HTML5 The attribute can be the ID of any form element in the same document. HTML 4 The attribute is null. Read only.
MDN
https://html.spec.whatwg.org/multipage/forms.html#htmlselectelement