How to return a value of a radio button in a group

Use the following function to get the value of the selected radio button in a group.

function checkRadio (frmName, radiobuttonGroupName) {
var radios = document[frmName].elements[radiobuttonGroupName];
for (var i=0; i < radios.length; i++) {
if (radios[i].checked) {
return radios[i].value;
}
}
return false;
}

selected = checkRadio (frmName, radiobuttonGroupName);