<form action=signup2.php method=post> <input type="text" length="40" value="name"><br> <input type=submit> </form>
<?php $name = $_POST['name']; mkdir($name); ?>
<form action=signup2.php method=post> <input type="text" length="40" name="name" value="name"><br> <input type=submit> </form>
<form action=signup2.php method=post> <input type="text" length="40" name="name" value="name" id="name"><br> <input type=submit> </form>