why undefined???

ajax-always-return.js

var func = function(str,id){
	var request = $.ajax({
		type: "get",
		url: "get_hogehge.php",
		data: {id: id}
	});
	request.done(function(data){});
	request.always(function(data){
		var result = "仮";
			console.log(result);// -> 仮
			console.log(typeof(result));// -> str
			return result;
  });
}
var ret_func = func(str,id);
console.log(ret_func); //-> undefined