The query string parameter is a URL with a query string

Here is an url like: http://laoqiren.me?callback=http://anothersite.com?name=jack&year=21, I want to callback to http://anothersite.com?name=jack&year=21, but I just get the callback's value: http://anothersite.com?name=jack. So how to get the correct callback value?