DOM2 HTMLButtonElement: missing blur/focus methods?

Dear W3C experts:

I'm just starting to dig in the W3C-recommendations,so I might miss
something very elementary, now. But I'm very confused by the following
opposition:

In the DOM2-Events-recommendation "focus" is a valid method for the
object "button, but in the DOM2-HTML-recommendation it's not mentioned
(just like in the DOM1-HTML-recommendation).

Could someone explain this? Thank you.


Resources:


Document Object Model Events
  http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html
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focus
    The focus event occurs when an element receives focus either via a
pointing device or by tabbing navigation. This event is valid for the
following elements: LABEL, INPUT, SELECT, TEXTAREA, and BUTTON.
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Document Object Model HTML
  http://www.w3.org/TR/2002/PR-DOM-Level-2-HTML-20021108/html.html
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Interface HTMLButtonElement

    Push button. See the BUTTON element definition in HTML 4.01.


    IDL Definition

interface HTMLButtonElement : HTMLElement {
  readonly attribute HTMLFormElement form;
           attribute DOMString       accessKey;
           attribute boolean         disabled;
           attribute DOMString       name;
           attribute long            tabIndex;
  readonly attribute DOMString       type;
           attribute DOMString       value;
};
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