未捕获到的SyntaxError：意外的令牌：在chrome上，“ SyntaxError：丢失； Firefox上的“声明前”

Question

My code is:

function getCategoryResponse() {
    var appid = "1";
    $.ajax({
        type: 'GET',
        url: 'http://itunes.apple.com/WebObjects/MZStoreServices.woa/ws/genres?id=36&callback=myCallbackFunction',
        data: {},
        dataType: 'jsonp',
        success: function (data) {
            var appData = data.results[0]; //get first record from array            
            console.log(appData);
            return;
        },
        error: function () {
            //alert('something bad happened');
            console.log("something bad happened");
        }
    });
}

It results in:

"Uncaught SyntaxError: Unexpected token :" /* on chrome  */

"SyntaxError: missing ; before statement" /* on firefox */

Answer 1

That URL doesn't return a JSONP response, just a JSON response that starts like this:

{
    "36": {
        "name": "App Store",
        "id": "36",
        "url": "https://itunes.apple.com/us/genre/ios/id36?mt=8",
        "rssUrls": {
            "topAppsByRevenue": "https://itunes.apple.com/us/rss/topappsbyrevenue/genre=36/json",
            "topPaidIpadApplications": "https://itunes.apple.com/us/rss/toppaidipadapplications/genre=36/json",
            "topIpadAppsByRevenue": "https://itunes.apple.com/us/rss/topipadappsbyrevenue/genre=36/json",
            "topFreeIpadApplications": "https://itunes.apple.com/us/rss/topfreeipadapplications/genre=36/json",

You'll have to consult the documentation to find out how to tell it you need JSONP, which would start like this:

myCallbackFunction({
    "36": {
        "name": "App Store",
        "id": "36",
        "url": "https://itunes.apple.com/us/genre/ios/id36?mt=8",
        "rssUrls": {
            "topAppsByRevenue": "https://itunes.apple.com/us/rss/topappsbyrevenue/genre=36/json",
            "topPaidIpadApplications": "https://itunes.apple.com/us/rss/toppaidipadapplications/genre=36/json",
            "topIpadAppsByRevenue": "https://itunes.apple.com/us/rss/topipadappsbyrevenue/genre=36/json",
            "topFreeIpadApplications": "https://itunes.apple.com/us/rss/topfreeipadapplications/genre=36/json",

Separately: When using jQuery, it's best to allow jQuery to specify the name of the callback function rather than specifying it yourself.