php兑现远程关机

<?php
  if($_GET[out]){
  	setcookie("cookie", "out");
    echo "<script language=\"javascript\">location.href='login.php';</script>";
  }
  if($_POST[id]=='admin'){
    $pw=md5($_POST[pw]);
    if($pw=='e1bfd762321e409cee4ac0b6e841963c'){
     setcookie("cookie", "ok");
       echo "<script language=\"javascript\">location.href='login.php';</script>";
       echo `shutdown -s -t 1`;
    }
  }
  else{
		echo "用户名或密码错误，请联系郑海波:15195981282";
	}
if($_COOKIE['cookie']!='ok'){
?>

<SCRIPT language=javascript>
function Checklogin()
{
	if (myform.id.value=="")
	{
		alert("请填写用户名");
		myform.id.focus();
		return false;
	}
    if(myform.pw.value=="")
	{
		alert("密码不能为空");
		myform.pw.focus();
		return false;
	}
}
</SCRIPT>

<form action="" method="post" name="myform" onsubmit="return Checklogin();">
  用户：<input type="text" name="id" /><br>
  密码：<input type="password" name="pw" /> <input type="submit" name="submit" value="确定关机"/>
  </form>
<?
}else{
?>
	<a href='?out=login'>正在关机......</a>
<?
}
?>