用php和html5表单发送多个文件

i have problem with send muliple files, for one file it works, for multiple not, what should I do with this code ?

if(isset($_FILES['pliki'])){
    $errors= array();
    $file_name = $_FILES['pliki']['name'];
    $file_size =$_FILES['pliki']['size'];
    $file_tmp =$_FILES['pliki']['tmp_name'];
    $file_type=$_FILES['pliki']['type'];
    $file_ext=strtolower(end(explode('.',$_FILES['pliki']['name'])));

    $expensions= array("jpeg","jpg","png","docx","doc","pdf");

    if(in_array($file_ext,$expensions)=== true){
        move_uploaded_file($file_tmp,"../../site/assets/files/".$pp->id."/".strtolower($sanitizer->name($file_name)));
        $pp->pliki->add($file_name);
    }
}

My input looks like this:

<input type="file" id="pliki" name="pliki[]" multiple> 

$_FILES['pliki'] would be an array so you need to loop through them. I would use something like:

$extensions = array("jpeg","jpg","png","docx","doc","pdf");
//extensions < spelling changed from yours

foreach($_FILES['pliki'] as $i => $file){
    $file_name = $file['name'];
    $file_size =$file['size'];
    $file_tmp =$file['tmp_name'];
    $file_type=$file['type'];
    $file_ext=strtolower(end(explode('.',$file_name)));
    //and whatever else you want to check for each file
}