선택된 라디오 버튼 값 반환

//선언
 function getSelectRadioBtn(radioVal){
  for(var i=0;i<radioVal.length;i++){
   if(radioVal[i].checked)
    return radioVal[i].value;
  }
  return -1;
 }

//호출
getSelectRadioBtn( document.getElementsByName('isuseroad') );