jQuery ajax调用webservice注意事项(2)

<script>
    $(function() {
      $("#userloging").show();
      //登录框处理开始
      //加载登录状态
      $.ajax({
        type: "POST", //访问WebService使用Post方式请求
        contentType: "application/json;charset=utf-8", //WebService 会返回Json类型
        url: "/API/Service/UserValidate.asmx/ValidateUserLogState", //调用WebService
        data: "{}", //Email参数
        dataType: 'json',
        beforeSend: function(x) { x.setRequestHeader("Content-Type", "application/json; charset=utf-8"); },
        error: function(x, e) { },
        success: function(response) { //回调函数，result，返回值
          $("#userloging").hide();
          var json = eval('(' + response.d + ')');
          var userid = json.user.id;
          if (userid > 0) {
            $("#spanusername").html(json.user.name);
            $("#spanmessagenum").html(json.user.message);
            $("#userloginsucced").show();
            $("#userloginbox").hide();
          }
        }
      });
      //登录
      $("#userlogbutton").click(function() {
        
        var username = $("#username").val();
        var userpwd = $("#userpassword").val();
        if (username != "" && userpwd != "") {
          $("#userloging").show();
          $.ajax({
            type: "POST", //访问WebService使用Post方式请求
            contentType: "application/json;charset=utf-8", //WebService 会返回Json类型
            url: "/API/Service/UserValidate.asmx/UserLogin", //调用WebService
            data: "{userName:'" + username + "',userPwd:'" + userpwd + "'}", //Email参数
            dataType: 'json',
            beforeSend: function(x) { x.setRequestHeader("Content-Type", "application/json; charset=utf-8"); },
            error: function(x, e) {
            },
            success: function(result) { //回调函数，result，返回值
              $("#userloging").hide();
              var json = eval('(' + result.d + ')');
              var userid = json.user.id;
              if (userid > 0) {
                $("#spanusername").html(json.user.name);
                $("#spanmessagenum").html(json.user.message);
                $("#userloginsucced").show();
                $("#userloginbox").hide();
              }
              else {
                switch (userid) {
                  case -2:
                    alert("用户被锁定！请30分钟后再登录！");
                    $("#username").focus();
                    break;
                  case -1:
                    alert("用户名或密码错误！请核对您的用户名和密码！");
                    $("#userpassword").focus();
                    break;
                  default:
                    alert("登录失败！请核对您的用户名和密码之后重试！");
                    $("#userpassword").focus();
                    break;
                }
              }
            }
          });
        }
        else if (username == "") {
          alert("用户名不能为空！");
          $("#username").focus();
        }
        else if (userpwd == "") {
          alert("密码不能为空！");
          $("#userpassword").focus();
        }
      });
      //退出
      $("#logout").click(function() {
        $("#userloging").show();
        $.ajax({
          type: "POST", //访问WebService使用Post方式请求
          contentType: "application/json;utf-8", //WebService 会返回Json类型
          url: "/API/Service/UserValidate.asmx/UserLogout", //调用WebService
          data: "{}", //Email参数
          dataType: 'json',
          beforeSend: function(x) { x.setRequestHeader("Content-Type", "application/json; charset=utf-8"); },
          success: function(result) { //回调函数，result，返回值
            $("#userloging").hide();
            if (result.d > 0) {
              $("#userloginsucced").hide();
              $("#userloginbox").show();
            }
          }
        });

      }); //登录框处理结束

    });
    </script>