jquery获取radio单选框的值

1.获取原有单选框的值

var value=$("input[name='is_setting']:checked").val();

2.获取重选后的单选框的值

<tr>
    <td>使用首末场设置：</td>
    <td>
        <input type="radio" name="is_setting" value="" <{if $activity.is_setting eq ""}> checked <{/if}>
                onchange="readonly($(this))" >是<br>
        <input type="radio" name="is_setting" value="" <{if $activity.is_setting eq ""}> checked <{/if}>
                onchange="readonly($(this))" >否
    </td>
</tr>

function readonly(obj){
    var value = obj.val();
}