!-- Multiple Checkboxes -->
    <?php
    mysql_connect("localhost", "user", "pass") or die("Connection Failed");
    mysql_select_db("sound")or die("Connection Failed");
    ?>
    <div class="control-group">
    <?php
    $query = "SELECT * FROM video";
    $result = mysql_query($query);
    while ($line = mysql_fetch_array($result, MYSQL_ASSOC)) {
    ?>
    <div class="controls">
        <label class="checkbox">
          <input type="checkbox" name="videoid" value="<?php echo $line[id]?>"><?php echo $line[title]?>
        </label>
      </div>
      <?php } ?>

    <!-- Button -->
    <div class="control-group">
      <label class="control-label" for="submit_select"></label>
      <div class="controls">
        <button id="submit" name="sub" class="btn btn-primary">Submit</button>
      </div>
    </div>

    </fieldset>
    </form>

     <?php
    if(isset($_POST['sub']))
    {
    $host="localhost";//host name
    $username="user"; //database username
    $password="pass";//database word
    $db_name="sound";//database name
    $tbl_name="selection"; //table name
    $con=mysqli_connect("$host", "$username", "$password","$db_name")or die("cannot connect");//connection string
    $user=$_POST['userid'];
    $checkbox1=$_POST['videoid'];
    $chk="";

    foreach($checkbox1 as $chk1)
       {
          $chk .= $chk1.",";
       }
    $in_ch=mysqli_query($con,"INSERT INTO tbl_selection (userid, videoid) VALUES ('$user', '$chk');");
    if($in_ch==1)
       {
          echo'<script>alert("Inserted Successfully")</script>';
       }
    else
       {
          echo'<script>alert("Failed To Insert")</script>';
       }
    }
    ?>
    </body>
    </html>