radio button required

Hi all, I have a page with only 4 radiobutton, but if user don't select any of them can go to the next step anyway. I would like to force user to select one or he can't go on.
I have inserted the validete-one-required but it doesn't work.
Can you help me?

Thanks

Francesco

Hi,

Please show me the code for the radio buttons and how did you configure the validation.

Regards,
Max