Adding validations to see if radio button is not selected

Question

I have the following code:

 
1. question 1

     Strongly         


        

Answer 1

#by javascript

function validate(){
if (checkRadio("question1") && checkRadio("question2") && checkRadio("question3")){
 return true;
}else{
alert("Please answer all Questions!");
 return false;
}
}
function checkRadio(name){
 var radio = document.forms.myForm[name];
for (var option in radio){
if(radio[option].checked){
 return true;
}
}
return false;
}