css pseudo-class （伪类）checked unchecked
checked
input[type="checkbox"]:checked
{/* styles */}
uncheckedinput[type="checkbox"]:not(:checked)
{/* styles */}
:unchecked does not exist in the level 3 Selectors or UI specs, nor has it appeared in level 4 of Selectors yet. The Selectors specs wouldn't bother to suggest using :not(:checked) were there such a pseudo-class.
http://stackoverflow.com/questions/8846075/css3-unchecked-pseudo-class
