使用Ajax下载gz文件

Question

I want to download a gz file using ajax but didn't work.

Here What I get:

x1H4sIAAAAAAAAC82dzW8bORLF7/orGsjBNuAATRaL/THIwZMou8Y6diDLi52T7djajbDxB2xlFvPfL4u0I42cKP0uTwMEOcxI8c9sVr1ikY/9avSqmh78ejSuTqeTs7fTs8m4en8y6avLq8X89...

AJAX:

                $.ajax({
                    type: 'POST',
                    url: base_url+'backups/create',
                    data: $(form).serialize(),
                    dataType: 'json',
                    cache: false,
                    success: function (data) {

                    }
                });