JSON帖子响应未定义/空laravel 5

in my head tag, I declared this

<meta name="csrf-token" content="{{ csrf_token() }}" />

and then my script

$(document).ready(function(){
    $.ajaxSetup({ headers: {'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content') } });

    $.post("/employees", {id : "1"}, function(response){
    if(response.success)
    {
        var branchName = $('#branchname').empty();
        $.each(response.employees, function(){
            $('<option/>', {
                value:$(this).user_no,
                text:$(this).firstname
            }).appendTo(branchName);
        });
    }
    }, 'json'); //end of json post request
}); //end of document ready

and my html select tag that used when displaying the json response

<select id="branchname"></select>

my route that use by the json post request

Route::post('employees', [
    'as' => 'employees', 'uses' => 'mot@getemployee'
]);

and my controller that used in route.

public function getemployee(){
    $branch_no = "1";
    $employees = mot_users::where("branch_no", $branch_no)->lists('firstname','lastname', 'user_no');
    return response()->json(['success' => true, 'employees' => $employees]);
}

Problem: Yes it did successfully response but seems the data is empty/undefined because my select box is empty yet occupied by several option tags like

<select id="branchname">
    <option></option>
    <option></option>
    <option></option>
    <option></option>
    <option></option>
    <option></option>
    <option></option>
    <option></option>
    <option></option>
</select>

and I tried like

$.each(response.employees, function(){
    alert($(this).user_no); //hoping to get the id that was on the json data response.
});

instead of

$.each(response.employees, function(){
    $('<option/>', {
        value:$(this).user_no,
        text:$(this).firstname
    }).appendTo(branchName);
});

but it gives me "undefined".

Questions: whats wrong with my code? am I missing something? why the select tag with an id branchname is empty? how can I pass the id post data key from route to my controller for querying stuff so that I dont have to manually set $branch_no variable instead use whats the json post request sent to the routes to controller?

PS: im newbie in laravel 5 so I'm just on the part on figuring things out. Any help, suggestions, recommendations, ideas, clues that could fix my issue would be greatly appreciated. Thank you.