php 文件上传，

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<?php
if ($_POST['submit']) {
 $file=$_FILES['file'];
         
           $type= $file['type'];
           echo  $type;
           $name= $file['name'];
           $tmp_name= $file['tmp_name'];
           $size= $file['size'];
           $error= $file['error'];
           $date=date('Y-m-d');
           $name_date=$date.'_'.$name;
           echo $name_date;
       switch ($type)  {
        case 'image/pjpeg':
         $ok=1;
        break; 
        case 'image/jpeg':
        $ok=1;
        break;
        case 'image/gif':
        $ok=1; 
        break; 
        case 'image/bmp':
        $ok=1;
        break; 
       }
   if ($error=='0' and  $ok=='1') {
   move_uploaded_file($tmp_name,'up/'.$name_date);
   echo "上传成功！"; 
   }
}
 
?>

<form action="file.php" method="POST" enctype="multipart/form-data">
上传文件:<input type="file" name="file">
<input type="submit" value="提交"  name="submit">
</form>