What kind of data does Yahoo! Messenger API return for requests?

I looked in the Yahoo! Messenger API documentation to see how can I get the access token and I found this:

The call looks like this:

https://login.yahoo.com/WSLogin/V1/get_auth_token?&login=username&passwd=mypassword&oauth_consumer_key=consumerkey

The result of this call is a single value, the RequestToken:

RequestToken=jUO3Qolu3AYGU1KtB9vUbxlnzfIiFRLP...

This token is then used for a second request, which exchanges the PART for an OAuth access token. You can find out more information on the standard method getting an access token here.

I guess that the result is a standard result, but I don't know what kind of data is this. I mean that it isn't XML or JSON.

I would like to convert such a string to JSON:

{
    RequestToken: "jU0..."
}

Is there any standard converter/parser or must I build one?

Also, another request can look like below:

Error=MissingParameters
ErrorDescription=Sorry, try again with all the required parameters.

and I want to convert it into JSON:

{
   Error: "MissingParameters",
   ErrorDescription: "Sorry, try again with all the required parameters."
}

It would be very easy to build such a parser, but I don't want to reinvent the wheel.

I decided to write my own function. If there is a standard algorithm to parse such a string leave a comment.

/*
 *  Transform a string like this:
 *
 *  "Field1=123
 *  Field2=1234
 *  Field3=5"
 *
 *  into an object like this:
 *
 *  {
 *      "Field1": "123",
 *      "Field2": "1234",
 *      "Field3": "5",
 *  }
 *
 * */
function parseResponse (str) {

    // validate the provided value
    if (typeof str !== "string") {
        throw new Error("Please provide a string as argument: " + 
                                                 JSON.stringify(str));
    }

    // split it into lines
    var lines = str.trim().split("\n");

    // create the object that will be returned
    var parsedObject = {};

    // for every line
    for (var i = 0; i < lines.length; ++i) {
        // split the line
        var splits = lines[i].split("=")
            // and get the field
            , field = splits[0]
            // and the value
            , value = splits[1];

        // finally set them in the parsed object
        parsedObject[field] = value;
    }

    // return the parsed object
    return parsedObject;
};