Required radio buttons

Hi Takayuki Miyoshi,

first of all, thanks for your work on the plugin!
I’ve red the FAQ and several posts on this forum about required radio buttons. With the current version of CF7, the form can be sent even if the user does not select an option in a radio button group (with no default). I get your point about the HTML4 spec saying it is required, but no browser checks this. More importantly though: the HTML5 spec differs! It makes no mention that radio buttons are initially required; instead there is a specific “required” attribute to be added to radio button input fields:
http://www.w3.org/TR/html5/forms.html#concept-input-required

I know that there are “exclusive” checkboxes in CF7, but I think that they are completely besides the point – multiple checkboxes are usually there to enable multiple selections. If I want a “yes/no” answer from my user, I will use a radio button WITHOUT a default. That’s what users expect, not checkboxes. I think many of the users of other “radio button” threads in this forum agree with that, judging from their posts.

So, could you please add a radio* required option, which sets the correct HTML5 required attribute and also add it to the JavaScript checking of CF7? That would be great.

Thank you very much!

https://wordpress.org/plugins/contact-form-7/