Not able to get the Integer value from ajax success function

Question

Hello all, I am new to Web API and try to get the HREmpID from my ajax response but unfortunetly I am getting undefined.Below screen shot will provide more information in case if you need.

 

 

 

And in the below code is of ajax code that will get the records from the api

 

 

$(document).ready(function () {
        var r = new Array();
        var j = -1;
        r[++j] = '<table border = 1><thead><tr><th>HREmpID</th><th>Name</th><th>Address</th><th>City</th><th>Action</th></tr></thead><tbody>'
        $.ajax({
            type: "GET",
            url: "/api/EmployeeAPI/",
            success: function (result) {
                //alert(result[0]["FirstName"]);
                for (var i in result) {
                    var data = result[i];
                    alert(result[0]["HREmpID"]);
                    r[++j] = '<tr>';
                    r[++j] = '<td>';
                    r[++j] = data.HREmpID;
                    r[++j] = '</td>';
                    r[++j] = '<td>';
                    r[++j] = data.FirstName + " " + data.LastName;
                    r[++j] = '</td>';
                    r[++j] = '<td>';
                    r[++j] = data.Address;
                    r[++j] = '</td>';
                    r[++j] = '<td>';
                    r[++j] = data.City;
                    r[++j] = '</td>';
                    r[++j] = '</tr>';
                }
                r[++j] = '</tbody></table>';
                $("#empDetails").html(r.join(''));
            }
        });
    });

but I always getting the undefined for HRempID. I don't know what is going wrong ? any help will be appreciate. Thanks in advance.