Here is a small function to get the value of a selected radio button without using jQuery:
function getRadioValue(name) {
var radios = document.getElementsByName(name);
for (var i = 0; i< radios.length; i++) {
if (radios[i].checked)
return radios[i].value;
}
}
If you do not care about compatibility with Explorer versions below 9:
document.querySelector('input[name="myradios"]:checked').value;