button-attr-form type=button popovertarget=mypopover form=form>type=button</button>
<button id=invalid-attr-form type=invalid popovertarget=mypopover form=form>invalid</button>
<button id=missing-attr-form popovertarget=mypopover form=form>missing</button>

<button id=reset-outside-form type=reset popovertarget=mypopover>reset</button>
<button id=submit-outside-form type=submit popovertarget=mypopover>submit</button>
<button id=button-outside-form type=button popovertarget=mypopover>type=button</button>
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