Get ID from database when a specific td is clicked

You problem is not clear to me but maybe this is a possible solution.

You can create a loop counter variable at top of the foreach loop and use this counter as row no in your code for example.

PHP Code:

$row_no = 0;
foreach ($query->result() as $row){
        $row_no++;
        echo "<tr data-row-no=". $row_now .">";
        echo "<td><input type='checkbox'></td>";
        echo "<td>" . $row->klantnaam . "</td>";
        echo "<td class='kiesproject'>" . $row->project . "</td>";
        echo "<td>" . $row->projectid . "</td>";
        echo "<td>" . $row->started . "</td>";
        echo "<td>" . $row->agenten . "</td>";
        echo "<td>" . $row->nog_benaderen . "</td>";
        echo "<td><a href='http://managementtool/index.php/Home/terugbel'>" . $row->terugbellen . "</td></a>";
        echo "<td>" . $row->BMNRUIT . "</td>";
        echo "<td>" . $row->parkeer . "</td>";
        echo "<td>" . $row->maxdatum . "</td>";
        echo "<td>" . $row->Eff_duur . "</td>";
        echo "<td>" . $row->InEff_duur . "</td>";
        echo "</tr>";
} 


 then with the help of jquery you can find the parent element of the clicked TD and then get the data attribute and get row no. like this.