获取radio标签值

      <td>
             是<input type="radio" name="userModel.phone_message_login" id="is_phone_message_login_Y" value="Y" onclick="displayAndHiddenBtn('d')" checked/>
             否<input type="radio" name="userModel.phone_message_login" id="is_phone_message_login_N" value="N" onclick="displayAndHiddenBtn('h')" />
      </td>

 $(document).ready(function() {
  var getValues = document.getElementsByName("userModel.phone_message_login");
  var chooseStr = "";
  //alert("start "+getValues.length);
  for(var i=0;i<getValues.length;i++){
   if(getValues.item(i).checked){
    chooseStr = getValues.item(i).getAttribute("value");
    break;
   }else{
      continue;
     }
  }
  if(chooseStr == 'Y'){
         var node = document.getElementById("mobilePhone").firstChild;
         //alert("@@@" + node.innerHTML);
         var add = document.createElement("font");
         add.setAttribute('color','red');
         add.innerHTML = "*";
         document.getElementById("mobilePhone").insertBefore(add,node);   
  }
 });