true to indicate that a
checkbox is neither checked nor cleared (unchecked); or
otherwise. The default value is
The indeterminate attribute can be used to indicate
whether the user has acted on a control. For example, setting indeterminate
true causes the check box to appear dimmed,
indicating neither a checked nor cleared state.
The value of the indeterminate attribute acts independently of the values of the checked and status attributes. Creating an indeterminate state is different from disabling the control. A check box in the indeterminate state can still receive the focus. When the user clicks an indeterminate control, the indeterminate state turns off and the check box toggles between cleared and checked as usual.
This is a DOM attribute only. There is no equivalent way of specifying indeterminate in the markup.
This attribute extends the HTMLInputElement interface.