ajax'GET'调用返回jsonp可以，但是回调会产生'undefined'数据 [英] ajax 'GET' call returns jsonp okay but callback produces 'undefined' data

问题描述

我正在使用HTML页面中的.ajax jquery调用来访问跨域Web服务.虽然我可以使用firebug看到jsonp数据，但我无法将其加载到变量中甚至无法显示出来(出于调试目的).尝试使用jsonpCallback，成功和完成函数检索数据始终会导致未定义"/空数据.

最终，我需要将数据保存到变量中.任何帮助将不胜感激！

$.ajax({
    data: {
        User: UserValue,
        GUID: GUIDValue
    },
    cache: false,
    dataType: "jsonp", // tried json
    type: "GET",
    crossDomain: true,
    jsonp: false,  // tried true
    jsonpCallback: function (saveData) {
        if (saveData == null) {
            alert("DATA IS UNDEFINED!");  // displays every time
        }
        alert("Success is " + saveData);  // 'Success is undefined'
    },
    url: "http://localhost/NotifMOD/NotifService.svc/GetAllMessages?callback=success?",
    async: false, // tried true
    error: function (XMLHttpRequest, textStatus, errorThrown) {
         console.log(textStatus, errorThrown);
    },
    complete: function (a, b) {
        alert(a); //[object Object]
        alert(b); // parseerror
    }
});

解决方案

在JSONP中，您必须在代码中定义函数.

jsonpCallback必须是此函数的名称，而不是函数.

请参见 http://api.jquery.com/jQuery.ajax/

您这样做:

function receive(saveData) {
    if (saveData == null) {
            alert("DATA IS UNDEFINED!");  // displays every time
    }
    alert("Success is " + saveData);  // 'Success is undefined'
}

$.ajax({
    data: {
        User: UserValue,
        GUID: GUIDValue
    },
    cache: false,
    dataType: "jsonp", // tried json
    type: "GET",
    crossDomain: true,
    jsonp: false,  // tried true
    jsonpCallback: "receive",
    url: "http://localhost/NotifMOD/NotifService.svc/GetAllMessages?callback=receive?",
    async: false, // tried true
    error: function (XMLHttpRequest, textStatus, errorThrown) {
         console.log(textStatus, errorThrown);
    }
});

I'm accessing a cross-domain webservice utilizing an.ajax jquery call from an html page. While I can see the jsonp data using firebug, I am not able to load it into a variable or even display it (for debugging purposes). Attempts to retrieve data using the jsonpCallback, success and complete functions always result in 'undefined' / null data.

Ultimately, I need to save the data to variables. Any assistance will be greatly appreciated!

$.ajax({
    data: {
        User: UserValue,
        GUID: GUIDValue
    },
    cache: false,
    dataType: "jsonp", // tried json
    type: "GET",
    crossDomain: true,
    jsonp: false,  // tried true
    jsonpCallback: function (saveData) {
        if (saveData == null) {
            alert("DATA IS UNDEFINED!");  // displays every time
        }
        alert("Success is " + saveData);  // 'Success is undefined'
    },
    url: "http://localhost/NotifMOD/NotifService.svc/GetAllMessages?callback=success?",
    async: false, // tried true
    error: function (XMLHttpRequest, textStatus, errorThrown) {
         console.log(textStatus, errorThrown);
    },
    complete: function (a, b) {
        alert(a); //[object Object]
        alert(b); // parseerror
    }
});

解决方案

In JSONP you must define your function in your code.

jsonpCallback must be the name of this function, not a function.

See http://api.jquery.com/jQuery.ajax/

You do it like this :

function receive(saveData) {
    if (saveData == null) {
            alert("DATA IS UNDEFINED!");  // displays every time
    }
    alert("Success is " + saveData);  // 'Success is undefined'
}

$.ajax({
    data: {
        User: UserValue,
        GUID: GUIDValue
    },
    cache: false,
    dataType: "jsonp", // tried json
    type: "GET",
    crossDomain: true,
    jsonp: false,  // tried true
    jsonpCallback: "receive",
    url: "http://localhost/NotifMOD/NotifService.svc/GetAllMessages?callback=receive?",
    async: false, // tried true
    error: function (XMLHttpRequest, textStatus, errorThrown) {
         console.log(textStatus, errorThrown);
    }
});

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