JSONP AJAX请求中的“未捕获的语法错误：意外的令牌：”

Question

I already read many answers on similar questions like this, but didn't find the right solution that worked for me so I have to ask. Here is my code :

$.ajax({
    url: 'http://beta.zelenaposta.sk/oauth/request-token',
    dataType: 'jsonp',
    type: 'POST',
    contentType: 'application/x-www-form-urlencoded',
    data: {
        oauth_consumer_key: some_value,
        oauth_signature: some_other_value,
        oauth_signature_method: 'PLAINTEXT'
    }
}).done(function(data) {
    console.log(data);
}).fail(function(jqXHR,errorThrown, data){
    console.log(errorThrown);
    console.log(jqXHR.responseText);
    console.log(jqXHR.status);
})

Here is how to get request token:

POST /oauth/request-token HTTP/1.1 
Host: zelenaposta.sk 
Content-Type: application/x-www-form-urlencoded 

oauth_consumer_key=some_value& 
oauth_signature=some_other_value& 
oauth_signature_method=PLAINTEXT

This request sends this response (if successful):

{
    "token": "some_new_value",
    "error": false,
    "errorMessage": null
}

And here is the error that i get :

errorThrown = parsererror
jqXHR.responseText = null
Uncaught SyntaxError: Unexpected token :

How can I get rid of these errors? I need to use JSONP because of cross site scripting and I don't have any access to the server where I'm posting the request. I would really appreciate any kind of help.

Answer 1

I had the same problem too, it turned out there were some special characters that caused a parsing error: character/substrings like "/", "/n", "/t" could not be parsed. What I did was a replace in my WebMethod function before returning the JSON.

        json = json.Replace("\\n", "\\\\n");
        json = json.Replace("\\t", "\\\\t");
        json = json.Replace("\\\"", "\\\\\"");

Note the number of backslashes in there :) I discovered what the problem was using Firefox and Firebug, the error had much more details than the one Chrome Console gave me. A very useful hint was the exact column where the parsing error occured, wich helped me locate the character.