PHP 编码函数和下拉声明

所以我的问题是编码没有插入到数据库中，日期选择器也有问题。

.html

    <?php
            include('connection.php');
            include('book.php');
        ?>
   <script language="javascript" type="text/javascript" src="datetimepicker.js">
   </script>   
   </header> 
    <!-- Main content -->
    <section class="row">
      <div class="grid">
            <label>
              Hour of Services
              <select name="quantity">
                <option value="1" selected>1 hour</option>
                <option value="2">1.5 hour</option>
                <option value="3">2 hour</option>
                <option value="4">2.5 hour</option>
                <option value="5">3 hour</option>
              </select>
              <span id="hourError" class="error"><?php echo $hourError; ?>  </span>
            </label>
           <label>
            Choose Date
            <input type="Text" id="demo1" maxlength="25" size="25"><a href="javascript:NewCal('demo1','ddmmmyyyy',true,24)"><img src="cal.jpg" width="16" height="16" border="0" alt="Pick a date"></a>
            <span class="descriptions">pick a date..</span>
             <span id="dateError" class="error2"><?php echo $dateError; ?></span>
</label>
<br>

            <label>
              Notes
     <textarea id="note" onblur="checknote()" name="note"><?php echo $note; ?></textarea>
                                <span id="noteError" class="error2"><?php echo $noteError; ?></span>
            <input class="btn btn-default" type="submit" name="submit" value="booking">
          </fieldset>
        </form>
      </div>
      </section>
      </body>
      </html>

PHP，我的声明有问题吗？

定义变量

    $username = "";
    $hour = "";
    $date = "";
    $note = "";

定义误差变量

    $usernameError = "";
    $hourError = "";
    $dateError = "";
    $noteError = "";

按下提交按钮时，执行此操作

    if (isset($_POST['submit'])) {
        $username = trim($_POST['username']);
        $hour = trim($_POST['hour']);
        $date = trim($_POST['date']);
        $note = trim($_POST['note']);

我的下拉菜单似乎不正确

        function checkhour($hour){
            global $hourError;
                 if ($hour === "pleaseselect") {
                $hourError = "Please choose an option from the drop down list";
                return false;
            }
            $hourError = "hour select!";
            return true;
        }

功能，以检查所有

 function checkAll($username, $hour, $date, $note){
     if (checkusername($username) & checkhour($hour) & checknote($note)) {
                    if(empty($errors)){
    $query = "INSERT INTO book (username,hour,date,note) VALUES ('$username','$hour',,'$date''$note')";
    $result = mysql_query ($query);
    if ($result)
        echo "<script language='javascript'>alert ('booked success!'); </script>";
    }
    checkAll($username, $hour, $date, $note);
    }
?>

我不知道，它只是日期，下拉菜单不起作用。 请帮忙