function answer_checker(form)
{
for (var e = 0; e < form.elements.length; e++) { 
var el = form.elements[e]; 
if (form.elements[e].type == 'radio') { 
var group = form[el.name]; 
var checked = false; 
if (!group.length) 
checked = el.checked; 
else 
for (var r = 0; r < group.length; r++) 
if ((checked = group[r].checked)) 
break; 
if (!checked) { 
alert('You have not answered all 10 questions'); 
el.focus(); 
return false; 
} 
} 

} 
return true; 
}