JQuery 得到radio

<div>
        <input id="Radio1" type="radio" name="rad" value="1" checked />1
        <input id="Radio2" type="radio" name="rad" value="2" />2
        <input id="Radio3" type="radio" name="rad" value="3" />3
        <input id="Radio4" type="radio" name="rad" value="4" />4
        <input id="Radio5" type="radio" name="rad" value="5" />5
        <input id="Button1" type="button" value="button" onclick="return Button1_onclick()" />
        <input id="Button2" type="button" value="button" onclick="return Button2_onclick()" />
    </div>

 <script language="javascript" type="text/javascript">
// <![CDATA[

        function Button1_onclick() {
            $("input").each(function () {
                if (this.type == 'radio') {
                    alert($(this).val());
                }
            });
        }

        function Button2_onclick() {
            //alert($("input[@type=radio]:checked").val());
            //alert($("input[name='rad']:checked").val());
            alert($("input[@type=radio]").val());
        }

// ]]>
    </script>