阿贾克斯不回头任何数据。

Ajax does not turn back any data.

http://jsfiddle.net/w67C4/

$.ajax({
    dataType:'jsonp',
    url: url,
    async:false,
    success: function(data){
        getUsername = data.user.id;
    },
});

返回数据为空，但返回的用户ID需要

Returning data is null but required to return the userId

推荐答案

您需要做的：

function getUserId() {
    var url = "http://api.flickr.com/services/rest/?jsoncallback=?&api_key=fc6c52ed4f458bd9ee506912a860e466&method=flickr.urls.lookupUser&format=json&nojsoncallback=1&url=http://www.flickr.com/photos/flickr";
    var getUsername = null;

    return $.ajax({
        dataType: 'jsonp',
        url: url,
        async: false
    });
}

getUserId().done(function (result) {
    // Call the alert here..
    alert(result.user.id);
});

FIDDLE