get_student.php

<?php
include('includes/config.php');

if (!empty($_POST["classid"])) {

  $cid = intval($_POST['classid']);

  if (!is_numeric($cid)) {

    echo htmlentities("invalid Class");
    exit;
    
  } else {
    $stmt = $dbh->prepare("SELECT StudentName,StudentId FROM tblstudents WHERE ClassId= :id order by StudentName");
    $stmt->execute(array(':id' => $cid));
?><option value="">Select Category </option><?php
                                              while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
                                              ?>
      <option value="<?php echo htmlentities($row['StudentId']); ?>"><?php echo htmlentities($row['StudentName']); ?></option>
    <?php
                                              }
                                            }
                                          }
                                          // Code for Subjects
                                          if (!empty($_POST["classid1"])) {
                                            $cid1 = intval($_POST['classid1']);
                                            if (!is_numeric($cid1)) {

                                              echo htmlentities("invalid Class");
                                              exit;
                                            } else {
                                              $status = 0;
                                              $stmt = $dbh->prepare("SELECT tblsubjects.SubjectName,tblsubjects.id FROM tblsubjectcombination join  tblsubjects on  tblsubjects.id=tblsubjectcombination.SubjectId WHERE tblsubjectcombination.ClassId=:cid and tblsubjectcombination.status!=:stts order by tblsubjects.SubjectName");
                                              $stmt->execute(array(':cid' => $cid1, ':stts' => $status));

                                              while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) { ?>
      <p> <?php echo htmlentities($row['SubjectName']); ?><input type="text" name="marks[]" value="" class="form-control" required="" placeholder="Enter marks out of 100" autocomplete="off"></p>

<?php  }
                                            }
                                          }


?>

<?php

if (!empty($_POST["studclass"])) {
  $id = $_POST['studclass'];
  $dta = explode("$", $id);
  $id = $dta[0];
  $id1 = $dta[1];
  $query = $dbh->prepare("SELECT StudentId,ClassId FROM tblresult WHERE StudentId=:id1 and ClassId=:id ");
  //$query= $dbh -> prepare($sql);
  $query->bindParam(':id1', $id1, PDO::PARAM_STR);
  $query->bindParam(':id', $id, PDO::PARAM_STR);
  $query->execute();
  $results = $query->fetchAll(PDO::FETCH_OBJ);
  $cnt = 1;
  if ($query->rowCount() > 0) { ?>
    <p>
      <?php
      echo "<span style='color:red'> Result Already Declare .</span>";
      echo "<script>$('#submit').prop('disabled',true);</script>";
      ?></p>
<?php }
} ?>