将数据用作$ .ajax中的对象

im trying to pass different parameters to data converting as an object, but im new in this and i need some help, this is my code:

$.ajax({
            url: 'http://....org/api/get_category_posts',
            dataType: 'jsonp',
            //data:'category_name=rock&count=2&order=desc',
            data: { 

                dataRock:'category_name=rock&count=2&order=desc', 
                dataPop:'category_name=pop&count=2&order=desc', 
                dataElectronica:'category_name=electronica&count=2&order=desc' 
            },

            success: function(data) {

                var albumsRock = function()
                {  

                    $('albumsRock').html(''); // vaciamos previamente el html

                    for(var i=0; i < data[dataRock].posts.length; i++)
                    {
                        addAlbum(data[dataRock].posts[i]);
                    }

                }

there are 3 parameters and i dont know how to access them, thanks!!

data being passed in has NOTHING to do with the data being sent back from the server. Your variable names are the same, that is about it. If you want to know what was sent up, use a local variable to hold the data.

var requestData = { 
    dataRock:'category_name=rock&count=2&order=desc', 
    dataPop:'category_name=pop&count=2&order=desc', 
    dataElectronica:'category_name=electronica&count=2&order=desc' 
};

$.ajax({
    url: 'http://....org/api/get_category_posts',
    dataType: 'jsonp',
    data: requestData,
    success: function(data) {
        console.log(requestData.dataRock);
    }
});

In your code, you have

data[dataRock].posts.length

I am assuming you want to use dataRock as a key since dataRock in the above is not an object

 data[requestData.dataRock].posts.length