PHP表单，如何在同一页面上回音？

好的，这里是情况，我想使用一个登录表单，例如

<form name="form1" method="post" action="sign.php">
    Username:<br/>
    <input name="myusername" type="text" id="myusername" /><br />
    Password:<br />
    <input name="mypassword" type="text" id="mypassword" /><br />
    <input type="submit" name="Submit" value="Login" />
</form>

用户名：



密码：

sign.php

<?php
ob_start();
$host="localhost"; // Host name 
$username="root"; // Mysql username 
$password=""; // Mysql password 
$db_name="cosmos"; // Database name 
$tbl_name="members"; // Table name

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect"); 
mysql_select_db("$db_name")or die("cannot select DB");

// Define $myusername and $mypassword 
$myusername=$_POST['myusername'];
$mypassword=$_POST['mypassword'];

// To protect MySQL injection (more detail about MySQL injection)
$myusername = stripslashes($myusername);
$mypassword = stripslashes($mypassword);
$myusername = mysql_real_escape_string($myusername);
$mypassword = mysql_real_escape_string($mypassword);
$mypassword = md5($mypassword);

$sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'";
$result=mysql_query($sql);

// Mysql_num_row is counting table row
$count=mysql_num_rows($result);
// If result matched $myusername and $mypassword, table row must be 1 row

if($count==1){
// Register $myusername, $mypassword and redirect to file "login_success.php"
session_register("myusername");
session_register("mypassword"); 
header("location:login_success.php");
}
else {
echo "Wrong Username or Password";
}

    ob_end_flush();
?>

---

测试是否出现POST。如果是，则验证凭证；如果正确，则重定向到目标页面；如果不正确，则显示错误消息。然后输出表单。
如果在表单标签后需要换行，请将表单包装在
标签
元素中（它们对这类事情很有用，请参见；）并给它
display:block
实际上这是演示表单：），谢谢这就像（isset（$\u POST[myusername]）{echo“Correct”}或者{echo“Failed”}