<textarea>没有正确发布信息

here is the code:

echo '<form id="register" action="index.php" method="post">
       <textarea form="register" name="mloc"></textarea>
       <input type="submit" value="continue" name="submit>"
       </form>';

on index.php:

$a=$_POST['mloc'];

this returns:

NOTICE: undefined index mloc on line 1

You don't need form="register" when textarea is inside the form. So:

echo '<form id="register" action="index.php" method="post">
       <textarea name="mloc"></textarea>
       <input type="submit" value="continue" name="submit>"
       </form>';