var fin1 = false;
var fin2 = false;
var fin3 = false;
$.ajax({
url: "address1",
success: function(){
fin1 = true;
fnUpdate();
}
});
$.ajax({
url: "address2",
success: function(){
fin2 = true;
fnUpdate();
}
});
$.ajax({
url: "address3",
success: function(){
fin3 = true;
fnUpdate();
}
});
function fnUpdate(){
if(fin1 && fin2 && fin3){
alert('fin');
}
}