跨域ajax无法正常工作

Question

I am having a problem while using cross-origin ajax.

I know it's a common question but did not get any solution for it yet.

$.ajax({    
  type: "GET",
  url: url,
  data: {id:id},
  dataType: "jsonp",
  crossDomain: true,  
  contentType: "application/jsonp; charset=utf-8",
  async: false,
  success: fnsuccesscallbackk,
  error: function(xhr, error){
    alert(error);
  },
  jsonpCallback: fnsuccesscallback   
});

function fnsuccesscallback(data){
  alert(data)
}

…but getting undefined response in callback function.

Is there anything wrong what I am doing.

Answer 1

After a lots of RND finally i got the solution of this.

Ajax function:
$.ajax({    
        type:"GET",
        url:'https://www.url.com/welcome/test_js',
        data:{name:'xyz'},
        crossDomain:true,
        dataType: "jsonp",
        jsonp: 'fnsuccesscallback',
         success: function(data) {
              alert(data.name)
        }
});


In the Php function:
function test_js() {
    echo $_GET['fnsuccesscallback'] . "(" . json_encode($_GET) . ")";
}