Storing values from dropdowns to Database using PHP - php

Question

I am working on an attendance module. Initially, it will show the list of all students along with a dropdown having options Present/Absent. The faculty member will choose Present/Absent accordingly & submit the same.
I am having problem in storing the corresponding values to the DB.
$sql = "select a.student_id, r.student_name, r.section, r.group_name, a.$subject from result.$batch r, attendance.$batch a where a.student_id = r.student_id AND r.section='$section'";
$c = 1;
$result1 = $result->query($sql);
if ($result1->num_rows > 0)
{
while($row = $result1->fetch_assoc())
{
echo '<tr>';
echo "<td>$c </td>";
echo "<td>{$row['student_id']}</td>";
echo "<td>{$row['student_name']}</td>";
echo "<td>{$row['section']}</td>";
echo "<td>{$row['group_name']}</td>";
echo "<td>
<select class='dropdown' id='attend' name='attend[$c]' > <option value='1'>Present</option> <option value='2'>Absent</option>
</td>";
echo '</tr>';
++$c;
}
}
else
{
echo "No Results Found";
}
Can someone please help me with the updation code. Updation is to be made in the table $batch (batch is a variable containing Table Name to use) and column $subject (contains variable name).

Answer 1

well, you can do one thing.when user clicks on the check-box to mark absent or present, save it into an array using Javascript like :
onclick='array.push(this.id);'
this would push the id of current element to an array in Javascript.
When you finally submit the form, just do this,
onsubmit="passValues();"
in script tag, do this
function passValues()
{
var x = array // the array to which elements were pushed
document.getElementById('someBlankElement').innerHTML = "<input type='hidden' value = 'display array here' name='get_this_name_through_php_when_form_submits' >"
}
and done !