PHP使用xml登录系统

Question

I am new to php and xml. I am trying to build a php login system using xml file but it is not working. I am trying to just verify username but it is not showing anything in the form page.

<?php
if(isset($_POST['login']))
{
   $n=$_POST['username'];
   $p=$_POST['password'];
   //echo $n;
   $xml1=simplexml_load_file("user.xml");
   if($xml1->username==$n)
   {
    echo 'Yahoo';
   } 
}
?>
<form action="" method="post">
Username:<input type="text" name="username"/><br>
Password:<input type="password" name="password"/><br>
<input type="submit" value="login" name="login"/>
</form>


<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE userlist[
<!ELEMENT userlist (user*)>
<!ELEMENT user (username,password)> 
<!ELEMENT username (#PCDATA)>
<!ELEMENT password (#PCDATA)>
]>

<userlist>
  <user>
  <username>ratan</username>
  <password>1234</password>
  </user>
</userlist>

Answer 1

Maybe you should retrieve the user entry:

$xml1=simplexml_load_file("user.xml");
$xmlUsername = $xml1->user->username;

Complete example: http://php.net/manual/en/simplexml.examples-basic.php