I want to do something like this:

$.ajax({
  url: SOMEWHERE,
  ...
  success: function(data){
    // do sth...
    var new_url = data.url;

    $.ajax({
      url: new_url,
      success: function(data){
        var another_url = data.url;

        // ajax call rely on the result of previous one
        $.ajax({
           // do sth
        })
      }
    })
  },
  fail: function(){
    // do sth...

    // ajax call too
    $.ajax({
      // config
    })
  }
})

the code looks like shit.

I wonder how to make it looks pretty. Some best practice?