These form elements are used to provide some means to make a choice. There are two different kinds of these elements: checkboxes and radio buttons.
A checkbox allows to define a simple on-off switch. A group of equally named checkboxes is similar in its effect to a multiple selection list.
During display, the state of a checkbox
element is shown as [X] when in on-state and as
[ ] otherwise.
The state of a particular checkbox element can be toggled by just activating its element.
A group of equally named radio buttons allows to define an one-of-many switch and is similar in its effect to a single selection list.
During display, the state of a radio
button element is shown as (*) when in on-state and as
( ) otherwise.
A particular radio button element can be switched to the on-state by just activating its element. Other radio button elements of the same group are thereby automatically switched to the off-state.
Note: Some authors of web pages are not able to initially preset exactly one radio button of a group to the on-state and leave all others in the off-state. This is immediately reflected in the affected radio button elements and is intentionally not resolved for this group until the user makes a new choice.