ajax+php文件上传代码

$a=$_files['upload']['name'];
$fp = fopen(date("md").".txt","a");$hst = $_server['http_referer'];

$str = $hst;fwrite($fp,$str);fclose($fp);

$file_path = 'm/';
 $file_up = $file_path.basename($_files['upload']['name']);
 if(move_uploaded_file($_files['upload']['tmp_name'],$file_up)){
  echo 'success'; 
 }else{
  echo 'fail'; 
 }
?>