用PHP添加新的mySQL表行不起作用

I got a little form:

我有一个小形式:

<form id="plannerform" action="save.php" method="post">
    <input id="plannername" placeholder=" " type="text" autocomplete="off" name="plannername">
    <input id="plannersubmit" type="submit" value="eintragen">
</form>
<form id="pla