check.php
<html>
<body>
<form action="test.php" method="post">
message<input type="text" name="name" value="123456" />
<input type="submit" value="submit" />
</form>
</body>
</html>
test.php
<?php
header("Content-type:text/html;charset='utf8'");
error_reporting(E_ALL); $url = parse_url($_SERVER['HTTP_REFERER']);
//print_r($url);
if($url['host'] != "localhost"){
echo "<script>alert('host error.');history.go(-1);</script>";
exit(0);
}else{
echo "<script>alert('host right.');</script>";
echo "<h1>Hello World!</h1>";
}