Question

我阅读了关于jQuery验证器的回复，其中概述了根据数据库中的值检查用户名的方法。

我已尝试实现此方法，但无论从PHP文件返回什么，我总是收到用户名已被删除的消息。

这是自定义方法......

$.validator.addMethod("uniqueUserName", function(value, element) {
  $.ajax({
      type: "POST",
       url: "php/get_save_status.php",
      data: "checkUsername="+value,
      dataType:"html",
   success: function(msg)
   {
      // if the user exists, it returns a string "true"
      if(msg == "true")
         return false;  // already exists
      return true;      // username is free to use
   }
 })}, "Username is Already Taken");

这是验证码......

username: {
    required: true,
    uniqueUserName: true
},

是否有一种特定的方式我应该从php返回消息。

由于

A

Answer 1

对于偶然发现此问题的其他人，验证支持“远程”方法，该方法可能在2010年不存在：

http://docs.jquery.com/Plugins/Validation/Methods/remote

$("#myform").validate({
  rules: {
    email: {
      required: true,
      email: true,
      remote: {
        url: "check-email.php",
        type: "post",
        data: {
          username: function() {
            return $("#username").val();
          }
        }
      }
    }
  }
});

Answer 2

你正在做一个AJAX请求，ergo：当你的自定义验证器返回true或false时，验证已经完成。

您需要使用async。另请参阅此帖子：How can I get jQuery to perform a synchronous, rather than asynchronous, Ajax request?

类似的东西：

function myValidator() {
   var isSuccess = false;

   $.ajax({ url: "", 
            data: {}, 
            async: false, 
            success: 
                function(msg) { isSuccess = msg === "true" ? true : false }
          });
    return isSuccess;
}

警告：

从jQuery 1.8开始，使用async：false和jqXHR（$ .Deferred）弃用;您必须使用success / error / complete回调选项而不是jqXHR对象的相应方法，如 jqXHR.done（）或不推荐使用的jqXHR.success（）。

Answer 3

我花了很长时间才弄清楚如何将包含页面中元素值的jsonified字符串放入远程请求中 - 这是多小时组合并尝试多次搜索结果的结果。

关键点：

async:false已弃用，

remote:之后的函数调用是用于创建具有元素值的数据字符串的键。在data:为dataType设置为json的字段返回空白值后，尝试从表单中访问当前值。

    $("#EmailAddress").rules("add", {
    required: true,
    remote: function () { // the function allows the creation of the data string 
                          // outside of the remote call itself, which would not 
                          // return a current value from the form.
        var emailData = "{'address':'" + 
                        $('#SignupForm :input[id$="EmailAddress"]').val() + 
                        "'}";
        var r = {
            url: "foobar.aspx/IsEmailAvailable",
            type: "post",
            dataType: "json",
            contentType: "application/json; charset=utf-8",
            cache: false,
            data: emailData,
            dataFilter: function(response) {
                this.email_run = true; //fix for race condition with next button
                return isAvailable(data); //return true or false
            }
        };
        return r;
    },
    messages: {
        remote: "* Email in use"
    }
});

.ASPX页面：

<input id="EmailAddress" required name="Email" type="email" placeholder="Email Address*" runat="server"/>

C＃代码背后：

[WebMethod]
    public static object IsEmailAvailable(string address){...}

格式化响应对象：

function isAvailable(data) {
    var response = JSON.parse(getJsonObject(data));
    return (response.isAvailable === "True") ? true : false;
};

//transform response string to a JavaScript Object()
//http://encosia.com/never-worry-about-asp-net-ajaxs-d-again/ 
function getJsonObject(data) {
    var msg = eval('(' + data + ')');
    if (msg.hasOwnProperty('d'))
        return msg.d;
    else
        return msg;
};

Answer 4

这是我的“老派”黑客...

下面是一个实用程序函数，该函数允许对“ jquery.validate.js”库使用“异步”验证。此功能会在用户击键之间产生延迟，否则验证功能“ validFunc”将被称为“ all time”，这在某些情况下效果不佳，对于在“服务器端” /“后端”执行验证的功能尤其有问题（ajax调用基本上是）。这样，仅当用户在一段时间内停止键入时才调用“ validFunc”验证功能，这也允许在用户键入时进行“实时”验证（jqv设置为"onkeyup": true）。

重要提示：涉及“ jqvAsyncValid”功能使用的验证应始终是最后一项，以避免由于异步而与其他冲突。

{
    [...]
    "rules": {
        "field_name": {
            "required": true,
            "maxlength": 12,
            "minlength": 4,

            // NOTE: Validation involving the use of the "jqvAsyncValid" function. By Questor
            "my_custom_ajax_validation": true

        },
    [...]
}

答案代码：

// NOTE: Adds the custom validation "my_custom_ajax_validation". By Questor
$.validator.addMethod("my_custom_ajax_validation", function (value, element) {
    return jqvAsyncValid(element, "my_custom_ajax_validation", myValidationFunc, this);
}, "My error message!");

// NOTE: My validation function. By Questor
function myValidationFunc(domElement) {
    if (someFuncWithAjaxCall(domElement.value) == "ALL_RIGHT!") {
        return true;
    } else {
        return false;
    }
}

// NOTE: Global "json" variable that stores the "status" ("isValid") and cycle control
// ("toCtrl") of asynchronously validated elements using the "jqvAsyncValid" function.
// By Questor
var jqvAsyncVState = {};

// NOTE: A utility function that allows the use of asynchronous validations with
// "jquery.validate.js". This function creates a delay between one user keystroke and
// another otherwise the validation function "validFunc" will be called "all time"
// which is not very performative in some circumstances and especially problematic
// for functions that perform validations on the serverside/backend (ajax calls basically).
// In this way the "validFunc" validation function is only called when the user stops
// typing for a certain period of time, which also allows a "realtime" validation
// as it occurs while the user is typing. By Questor
// [Ref .: https://jqueryvalidation.org/ ]
//. domElement - DOM element informed by jqv in the "addMethod" for the anonymous
// function;
//. asyncRuleNm - Validation name added via "addMethod";
//. validFunc - Function that will do the validation. Must have the signature
// "funcName(domElement)" returning "true" for valid and "false" for not;
//. jQValidInst - Instance of the current jqv within "addMethod". It is usually
// denoted by "this";
//. toInMsecs - "Timeout" in "milliseconds". If not informed the default will be
// 1500 milliseconds. Be careful not to use a very short timeout especially in
// "ajax" calls so as not to overload the serverside/backend.
// Eg.: `return jqvAsyncValid(element, "my_custom_ajax_validation", myValidationFunc, this);`.
function jqvAsyncValid(domElement, asyncRuleNm, validFunc, jQValidInst, toInMsecs) {
    if (typeof toInMsecs === "undefined" || toInMsecs === "") {
        toInMsecs = 1500;
    }
    var domEKey = jQValidInst.currentForm.id + domElement.name;

    // NOTE: The validation messages need to be "displayed" and "hidden" manually
    // as they are displayed asynchronously. By Questor
    function errMsgHandler() {
        if (jqvAsyncVState[domEKey]["isValid"]) {

            // NOTE: If the current error message displayed on the element was that
            // set in the rule added via "addMethod" then it should be removed since
            // the element is valid. By Questor
            // [Ref.: https://stackoverflow.com/a/11652922/3223785 ,
            // https://stackoverflow.com/a/11952571/3223785 ]
            if (jQValidInst.errorMap[domElement.name] == $.validator.messages[asyncRuleNm]) {
                var iMsgNow = {};
                iMsgNow[domElement.name] = "";
                jQValidInst.showErrors(iMsgNow);
            }

        } else {
            var iMsgNow = {};

            // NOTE: If the element is invalid, get the message set by "addMethod"
            // for current rule in "$.validator.messages" and show it. By Questor
            iMsgNow[domElement.name] = $.validator.messages[asyncRuleNm];
            jQValidInst.showErrors(iMsgNow);

        }
    }
    if (!jqvAsyncVState.hasOwnProperty(domEKey)) {

        // NOTE: Set the global json variable "jqvAsyncVState" the control attributes
        // for the element to be asynchronously validated if it has not already been
        // set. The key "domEKey" is formed by the "id" of the "form" that contains
        // the element and the element's "name". By Questor
        jqvAsyncVState[domEKey] = {
            "toCtrl": null,
            "isValid": undefined
        };

    }
    var useOnKeyup = true;

    // NOTE: The "onblur" event is required for "first validation" that only occurs
    // in a "blur" event - this is inherent to jqv - and for situations where the
    // user types very fast and triggers "tab" and the event "onkeyup" can not deal
    // with it. By Questor
    domElement.onblur = function (e) {
        jqvAsyncVState[domEKey]["isValid"] = validFunc(domElement);
        errMsgHandler();
        useOnKeyup = false;
    }
    if (useOnKeyup) {

        // NOTE: The strategy with the event "onkeyup" below was created to create
        // a "delay" between a "keystroke" and another one otherwise the validation
        // function "validFunc" will be called "all time" which is not very performative
        // in some circumstances and especially problematic for functions that perform
        // serverside/backend validations (ajax calls basically). In this way the
        // "validFunc" validation function is only called when the user stops typing
        // for a certain period of time ("toInMsecs"). By Questor
        domElement.onkeyup = function (e) {

            // NOTE: Clear the "toCtrl" if it has already been set. This will
            // prevent the previous task from executing if it has been less than
            // "toInMsecs". By Questor
            clearTimeout(jqvAsyncVState[domEKey]["toCtrl"]);

            // NOTE: Make a new "toCtrl" set to go off in "toInMsecs" ms. By Questor
            jqvAsyncVState[domEKey]["toCtrl"] = setTimeout(function () {
                jqvAsyncVState[domEKey]["isValid"] = validFunc(domElement);
                errMsgHandler();
            }, toInMsecs);
        };
    }
    return jqvAsyncVState[domEKey]["isValid"];
}

jQuery验证器和使用AJAX的自定义规则

4 个答案: