How to make a jsonp POST request that specifies contentType with jQuery?

Use json in dataType and send like this:

        $.ajax({
            url: "your url which return json",
            type: "POST",
            crossDomain: true,
            data: data,
            dataType: "json",
            success:function(result){
                alert(JSON.stringify(result));
            },
            error:function(xhr,status,error){
                alert(status);
            }
        });

and put this lines in your server side file:

if PHP:

header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: POST');
header('Access-Control-Max-Age: 1000');

if java:

response.addHeader( "Access-Control-Allow-Origin", "*" ); 
response.addHeader( "Access-Control-Allow-Methods", "POST" ); 
response.addHeader( "Access-Control-Max-Age", "1000" );