while ($row = mysqli_fetch_array($r, MYSQLI_ASSOC)) {
$display1=$display1+1;
    echo '
    <tr class="tablerow">
        <td>' . $row['id'] . '</td>
        <td><p class="state">' . $row['name'] . '</p></td>
        <td><p class="state">' . $row['surname'] . '</p></td>
        <td>' . $row['country'] . '</td>
        <td>' . $row['city'] . '</td>
        <td>' . $row['category'] . '</td>
    </tr>';
if($row['id']==$_GET['showrow'])
{
    echo '
    <tr class="subtable" style="display:none;">';
        echo '<td colspan="3" class="detalji"></td>
        <td align="left" colspan="3" class="detalji"></td>
        </tr>';}} // End of WHILE loop.
echo '</table>';

/* Table row click */
$(".tablerow").click(function()
{
  $(".subtable").show();
});

$(".subtable").click(function()
{
  $(".subtable").hide();
});

$(".tablerow").click(function() {
    // Hideing all the tr with class subtable rows initially
    $('.subtable').hide();
    // Find the next tr which has class subclass in current context
    $(this).next('.subtable').show();
});

$(".subtable").click(function() {
    // Hide current row that has class subtable
    $(this).hide();
});​

$(".tablerow").click(function()
{
  $(this).next(".subtable").slideDown("slow");
});

$(".subtable").click(function()
{
  $(".subtable").hide();
});