How to make 'other' radio button a mandatory entry

I have a radio button field with three optons plus 'other'.

It is a required field

I have not entered a default placeholder value for the 'other' option.

How can I force an entry to be made if the user chooses 'other'? At present you can chosse the empty selection and it saves the value as "other" in the database.

I have read several threads on the forum, (some of which relate to checkboxes) and it appears this logic has been changed. I assumed that if I entered placeholder text then this would count as an entry if it was selected, but if the placeholder was blank then it would require a user entry. Unfortunately this is not how it is working.

Can you please offer a solution. 

I do see you an abundant amount of forms. Please provide the Name or Form URL of the form in question to assist you better.

User entry should be require for any unfilled radio button field, unless you have a value already selected by default which can be set on the fields properties.

Thank you.

Please refer to my test form http://www.jotform.com//?formID=41175871639968

 If the blank option is selected then the value "Other" is input as data - but I need to make the user enter his own data. I thought that if there was no default placeholder for this option then it would force user entry but it doesnt.

No way to make it mandatory as of now, but I will submit a ticket to our development team to see if they can have it implemented.

We will let you know if and when the change is applied to the form builder.

Thank you