JS判断页面中的radio是否选中

<script language="javascript">
function clicked()
{
for(var i=0;i<document.mxh.radio.length;i++)
{
if(document.mxh.radio[i].checked)
alert(document.mxh.radio[i].value+":选了")
else
alert(document.mxh.radio[i].value+":没选") }
}
</script>

<form name=mxh>
<input type=radio name=radio value=1>1
<input type=radio name=radio value=2>2
<input type=radio name=radio value=3>3
<input type=radio name=radio value=4>4
<input type=radio name=radio value=5>5
<input type=button value="查询" onclick=clicked()>
</form>