Question

I know this question has been asked, but I cannot get it working.

I execute the following AJAX request:

function dislikeMeme(memeId) {
    $.ajax({
        dataType: "jsonp",
        url: "http://<url>.com/dislike/" + memeId,
        data: { 
            u: "username",
            p: "password"
        },
        jsonpCallback: 'successCallback'
    });
}

function successCallback(data) {
    alert("Test"); // Not firing because of previous 'Invalid label' error
};

Looking at firebug I see that the request was successful, but there is an Invalid Label error which fires the Error callback of the request. The response of the request is as follows:

{
    "id":6220673,
    "myScore":-1,
    "msg":"Not loved"
}

I see that the parentheses are causing JavaScript to interpret the response as an object, but I know this is the format I am retrieving, isn’t there anyway to parse this before it causes an error?

I also see that the URL of the page returning this information is:

http://<url>.com/dislike/123456?callback=successCallback&u=username&p=password&_123456789

Everything is working perfectly except this Invalid label error. Does anyone have any ideas?

Thanks in advance everyone

Answer 1

A server that can handle JSONP takes the callback paramater (can be different parameter depending on WS) and passes it in the response. So the response from the server should be:

successCallback({
"id":6220673,
"myScore":-1,
"msg":"Not loved"
})

If you don’t have control over the server your only route is proxy. See my cross domain answer for information on getting around same origin policy.
What prevents me from using $.ajax to load another domain's html?