如何只将excel和csv文件上传到上传文件夹

i just need to grant access only to upload .csv and .xlsx files to my uploading folder. so what modifications should i do in the following coding.

<?php  if (isset($_POST["submit"])) {
    if (isset($_FILES["file"])) {
//        $_SESSION['date_ss'] = $_POST['date_ss'];
//if there was an error uploading the file
        if ($_FILES["file"]["error"] > 0) {
            echo "Return Code: " . $_FILES["file"]["error"] . "<br />";
        } else {
            if (file_exists($_FILES["file"]["name"])) {
                unlink($_FILES["file"]["name"]);
            }

            $target_path = "uploads/";
            $target_location = $target_path . basename($_FILES['file']['name']);
            $_SESSION['target_location'] = $target_location;


//            $datess = $_POST['date_ss'];
            move_uploaded_file($_FILES["file"]["tmp_name"], $target_location);
            $uploadedStatus = 1;

        }
    } else {
        echo "No file selected <br />";
    }
}
?>

$name=basename($_FILES['file']['name']);
$name1=explode('.',$name);
if($name1[count($name1)-1]=='csv'||$name1[count($name1)-1]=='xlsx')
{
          $target_path = "uploads/";
        $target_location = $target_path . basename($_FILES['file']['name']);
        $_SESSION['target_location'] = $target_location;
        move_uploaded_file($_FILES["file"]["tmp_name"], $target_location);
        $uploadedStatus = 1;
}