php引导数据表服务器

我在应用程序中使用引导数据表。我使用服务器端使用ajax从mysql数据库中获取值。

$(document).ready(function() {
    var dataTable = $('#employee-grid').DataTable( {
        "processing": true,
        "serverSide": true,
        "ajax":{
            url :"employee-grid-data.php", // json datasource
            type: "post",  // method  , by default get
            error: function(){  // error handling
            $(".employee-grid-error").html("");
            $("#employee-grid").append('<tbody class="employee-grid-error"><tr><thcolspan="3">No data found in the server</th></tr></tbody>');
            $("#employee-grid_processing").css("display","none");
        }
    }
} );

在employee-grid-data.php 中

while( $row=mysqli_fetch_array($query) ) {  // preparing an array
    $nestedData=array(); 
    $nestedData[] = $row["employee_name"];
    $nestedData[] = $row["employee_salary"];
    $nestedData[] = $row["employee_age"];
    $data[] = $nestedData;
}
$json_data = array(
    "draw"            => intval( $requestData['draw'] ),   // for every request/draw by clientside , they send a number as a parameter, when they recieve a response/data they first check the draw number, so we are sending same number in draw. 
    "recordsTotal"    => intval( $totalData ),  // total number of records
    "recordsFiltered" => intval( $totalFiltered ), // total number of records after searching, if there is no searching then totalFiltered = totalData
    "data"            => $data   // total data array
);
echo json_encode($json_data);  // send data as json format

所以我想要的是——我想为每个tr行添加单独的类。在数据表中，我看不到任何tr。那么我如何向tr添加一个类。（根据条件，tr的背景颜色不同）。