PHP Variable with Array

Answer 1

First, this doesn't make much sense (the assignment doesn't output anything printable):

echo '<tr>'.$id[]=$rows['id'].'';

This does the same yet it's clearer (the first line, since in a loop, will go on storing all the ids in an array):

$id[] = $rows['id'];
echo '<tr>';

UPDATE: Anyways there's no need to store the ids in an array here, just use $row['id'] to print the user identifier in the option value (right now no value is set):

while($row = mysql_fetch_array($result))
{
echo    '<tr>';
echo    '<td width="50px" align="center" class="TableFormCell"><input type="checkbox" name="option[]" value="' . $row['id'] . '"/></td>';
echo    '<td width="170px" align="center" class="TableFormCell">'.$row['uname'].'</td>';
echo    '</tr>';
}

The form action script will receive a $_POST['option'] variable containing the selected ids. An example of how it can be used:

$ids = array();
// input filtering: convert all values to integers
foreach($_POST['option'] as $id)
{
    $ids[] = (int)$id;
}    
if(!empty($ids)) {
    // if there's at least one selected user
    $sql1 = "UPDATE ninos SET power = '$power' Where id IN (" . implode(',', $ids) . ")";
    // execute the query (...)
}