jquery---ajax

<script type="text/javascript">
        //页面加载后
        $(function() {
            //给验证码图片添加点击事件
            $("#verId,#verId2").click(function() {
                //让img的src属性重新赋值为image.jsp
                $("#verId").attr("src", "image.jsp?date=" + new Date());
            })
        })

        function login() {
            //获取用户输入数据
            var unameval = $("#unameid").val();
            var pwdval = $("#pwdid").val();
            var verifycodeval = $("#verifycodeid").val();

            $.ajax({
                url : "user.action",
                type : "post",
                data : {
                    cmd : "login",
                    username : unameval,
                    password : pwdval,
                    verifycode : verifycodeval
                },
                dataType : "json",
                success : function(data) {
                    if (data.msgId == 1) {
                        window.location.href = "index.jsp";
                    } else if (data.msgId == 2) {
                        $("#passwordlabelid").html(data.msgContent);
                    } else if (data.msgId == 3) {
                        $("#verifycodelabelid").html(data.msgContent);
                    }
                }

            })
        }
    </script>