Upload files and register simultaneously by a single AJAX

I am able to Upload files by AJAX call through a handler by appending the file name and file and sending it to handler as shown below

var fileUpload = $("#file").get(0);

var files = fileUpload.files;

var test = new FormData();

for (var i = 0; i < files.length; i++) {

test.append(files[i].name, files[i]);

}

And while Registration, stringifying the values as shown and sending the JSON to a webmethod in aspx.cs page.

var requestData = { "A": B, "AA": BB, "AAA": BBB },

data: JSON.stringify(requestData)

Now how can i do both the processes in a single AJAX call and further how can I retreive the values in ProcessRequest of Handler.