The checkbox object makes a check box in an HTML form available in JavaScript.
checked— A Boolean value indicating whether the check box element is checked.
defaultChecked— A Boolean value indicating whether the check box element was checked by default (that is, it reflects the checked attribute).
enabled— A Boolean value indicating whether the check box is enabled. (Not 2|3.)
form— A reference to the form object containing the check box. (Not 2|3.)
name— A string value containing the name of the check box element.
type— A string value reflecting the TYPE attribute of the <input/> element. (Not 2|I.)
value— A string value containing the value of the check box element.