function output(msg){
$("#debug").append("<p>"+msg+"</p>");
}
function work1(callback){
output("begin work1");
$.get('data.js', function(data){
output("end work1");
if(typeof callback == 'function'){
callback();
}
});
}
function work2(callback){
output("begin work2");
$.get('data.js', function(data){
output("end work2");
if(typeof callback == 'function'){
callback();
}
});
}
function work3(callback){
output("begin work3");
$.get('data.js', function(data){
output("end work3");
if(typeof callback == 'function'){
callback();
}
});
}

work1();
work2();
work3();

begin work1
begin work2
begin work3
end work1
end work2
end work3

var
 callback3 
=

 

function
 
(){work3();};


var
 callback2 
=
 function
 
(){work2(callback3);};


var
 callback1 
=
 function

(){work1(callback2);}
callback1();

begin work1
end work1
begin work2
end work2
begin work3
end work3

function

 AsyncWorkManager(){
    

this

.works 

=

 [];
}
AsyncWorkManager.prototype.addWork 

=

 

function

(callee, caller){
    

if

(

typeof

 callee

!=

 

'

function

'

)
        

throw

 {name:

"

TypeError

"

,message:

"

work must be a function

"

};
    

this

.works.push([callee, caller])