Adding validations to see if radio button is not selected

Question

I have the following code:

 
1. question 1

     Strongly         


        

Answer 1

It looks like you're using only javascript. I recommend you adding jQuery to make writing javascript easier.

Anyway, only using javascript you can try this:

var questions = 30;
var answer_checked = false;
var one_not_checked = false;
for (var i = 1; i <= questions; i++) {
    for (var j=0; j < document.getElementsByName('question'+i).length; j++) {
        answer_checked = answer_checked || (thisfrm['question'+i][j].checked == true);
    }
    one_not_checked = one_not_checked || !answer_checked;
    answer_checked = false;
}

if (one_not_checked) {
    // your message to the user as one answer is not checked
}