Javascript Jquery自定义验证器-检查值是否有效？

我创建了一个Jquery自定义验证器，如下所示

        var response;
    $.validator.addMethod(
        "uniqueUserName",
        function (value, element) {

            $.ajax({
                type: "POST",
                url: "/umbraco/surface/MemberShipSurface/ValidatePostCode",
                data: JSON.stringify({ PostCode: value }),
                contentType: "application/json; charset=utf-8",
                success: function (msg) {
                    alert(msg.istrue);
                    response = msg.istrue;

                }
            });
            return response;
        },

        "wrong postcode"
    );
    $("#reg-form").validate({
    rules: {
        day: {
            required: true,
            range: [01, 31]
        }, 
        PostCode: {
            required: true,
            number: true,
            maxlength: 4,
            minlength: 4,
            uniqueUserName: true
        }
    },

    errorElement: "span",

    submitHandler: function (form) {      
    }
});

如果ajax的输出为true，则表示验证成功，我们不需要显示任何错误消息，也不需要显示错误消息。但现在，我在表格上输入的任何值，第一次显示为错误，第二次显示为验证成功。有人能指出我做错了什么吗？

有可用的，你可以这样使用它

rules: {
    day: {
        required: true,
        range: [01, 31]
    },            
    PostCode: {
      required: true,
      number: true,
      maxlength: 4,
      minlength: 4,
      remote: {
        url: "/umbraco/surface/MemberShipSurface/ValidatePostCode",
        type: "post",
        data: {
          PostCode: function() {
            return $( "#PostCode" ).val();
          }
        }
      }
    }
}

如果要使用自定义方法，请在调用中使用

async=false

var response=false;
$.ajax({
    type: "POST",
    async:false,// now it will wait until you get response
    url: "/umbraco/surface/MemberShipSurface/ValidatePostCode",
    data: JSON.stringify({ PostCode: value }),
    contentType: "application/json; charset=utf-8",
    success: function (msg) {
        response = msg.istrue;
    }
});
return response;

试试这个

    var response= false;
    $.validator.addMethod(
        "uniqueUserName",
        function (value, element) {

            $.ajax({
                type: "POST",
                url: "/umbraco/surface/MemberShipSurface/ValidatePostCode",
                data: JSON.stringify({ PostCode: value }),
                contentType: "application/json; charset=utf-8",
                success: function (msg) {
                    alert(msg.istrue);
                    response = msg.istrue === "true" ? true : false;

                }
            });
            return response;
        },

        "wrong postcode"
    );
    $("#reg-form").validate({
        rules: {
            day: {
                required: true,
                range: [01, 31]
            }, 
            PostCode: {
                required: true,
                number: true,
                maxlength: 4,
                minlength: 4,
                uniqueUserName: true
            }
        },

        errorElement: "span",

        submitHandler: function (form) {      
        }
    });

---

声明此

var响应=false不工作。与我上面提到的相同的问题再次发生在msg.istrue的值上？如果数据有效，则为true，如果数据错误，则为False。您可以创建一个小提琴吗？此代码没有显示任何错误消息，说明我输入的任何数据以及您在
msg.istrue
中返回的值？