Radio Button Validation

4. Validation

Validation of groups of radio buttons is straightforward. The following function will validate for you that one of the radio buttons in a group has been selected:

All that you need to do to use the above function is to call it from within your form validation routine passing it the radio button group that is to be validated and it will return the value of the button within the group that is selected or null if no button in the group is selected.

For example the code that I used in the example form to perform the radio button validation is as follows:

This code was included into the function called by an onclick event attached to the validate (or submit) button on the form. A reference to the whole form was passed as a parameter into the function which uses the "form" argument to refer to the complete form. To validate the radio button group with the name group1 we therefore pass form.group1 to the valButton function.

I said at the start that defining radio buttons and their validation is the simplest of form fields to handle. All of the radio button groups that you will ever need can be handled using the steps that I have covered here.