$.ajax()
.then(function(){
return $.ajax() //second ajax call
})
.then(function(){
return $.ajax() //third ajax call
})
.done(function(resp){
//handle final response here
})
$.ajax()
.then(function(){
return $.ajax() //second ajax call
})
.then(function(){
return $.ajax() //third ajax call
})
.done(function(resp){
//handle final response here
})