js获取<s:radio>的值

<s:radio    name="isCharge" id="isCharge" list="#{'Y':'是','N':'否'}"
        listKey="key" listValue="value" value="'Y'" onchange="status();" />

<script type="text/javascript">
  function status() {
      var h=document.getElementsByName('isCharge')[0].checked;         
      if(h==false) {
          document.getElementById("songPrice").value=""
          document.getElementById("songPrice").disabled=false;
      }else {
          document.getElementById("songPrice").disabled=true;
      }   
  }
</script>