This page illustrates the use of a text box, hidden
variables, radio buttons, selection lists (two variations),
textarea, reset button, submit button, checkbox, and a
miscellaneous button, Take this questionnaire twice. Fill it out exactly the
same, except one time check both checkboxes. The other time,
leave both checkboxes blank. When you examine the data, you'll
see that the data file is not correct, and the missing checkboxes
are not the only problem. This is a reason to avoid checkboxes
when you intend to analyze the data with a statistical package. Use radio buttons instead.