Reading a Single Attribute Property in jQuery

You can not only change the values ​​of attributes-properties, but also read them. For example, the input specifies the property disabled:

html<input type="text" id="test" disabled>

We specify only the disabled property for the attribute, without boolean values:

javascriptalert($('#test').prop('disabled')); // will bring out 'true' - attribute is
Задание 1

Set all checked checkboxes to unchecked.

Задание 2

Set all unchecked checkboxes to checked.

Задание 3

Set all checked checkboxes to unchecked and vice versa.