Validation of radio and check boxes input

Below is a simple form with checkboxes and radio buttons, please fill it in.

• In the head, some JavaScript code that defines a "give_feedback" function is loaded
• Checkboxes are a bit more difficult to handle than radio buttons. Also, unlike radio buttons you can choose to differentiate between check boxes by either giving same name to a series of checkboxes with different values or alternatively by giving each checkbox its own name. In the latter case no value is needed for processing, but you could give one.
• To decide if a user checked a checkbox, you need to look at the "checked" property. In the first case you have to retrieve the element by an index, in the second you don't need to.
• Radio buttons are as tricky as multiple checkboxes with the same name. To check whether the user selected a value and at the same time to retrieve a selection we wrote a little function. function get_selected_radio_value (list) will take a DOM node list representing a series of checkboxes.
• JavaScript code is inside this page ...

Validation of radio and check boxes input