<!doctype html>
<html>
<head>
<meta charset="UTF-8">
<title>Untitled Document</title>
</head>
<style type="text/css">
    p{color:ghostwhite;
      height: 10px;}
    .mess{
        border: solid red 1px;
        text-align: center; 
        width: 400px;
        height: 130px;
        background-color: cadetblue;
    }
</style>    
<body>
<?php error_reporting(0); ?>
<div align="center" class="mess">    
<form method="post" id="confirm" action="#">
    <br>
    <p>ต้องการลบข้อมูลใช่หรือไม่ ?</p>
    <p> (ใส่ได้เฉพาะ 'Y/y' => ใช่ หรือ 'N/n' => ไม่ใช่ => Enter)</p>
    <input type="text" name="conf" size="1" pattern="[nyNY]" required>
    <!-- <input type="submit" value="ส่ง"> -->
    <?php if($_POST['conf']=='Y' OR $_POST['conf']=='y'){echo "yes";}
           else if($_POST['conf']=='N' OR $_POST['conf']=='n'){echo "no";}
    ?>
</form>
</div>    
</body>
</html>