我写的php代码上传图像从客户端到主机和网站，我的问题是，如果我刷新页面，最后一个文件将再次上传，它将被复制，如果再次刷新这个问题再次发生
我的代码：

<?php
$target_dir = 'C:\xampp\htdocs\upload\upload\jpg\\';
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$filename=basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));
$move=$_FILES["fileToUpload"]["tmp_name"];
 $isss=1;

// Check if image file is a actual image or fake image
// if(isset($_POST["submit"])) {
//   $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
//   if($check !== false) {
//     echo "File  - " . $check["mime"] . ".";
//     $uploadOk = 1;
//   } else {
//     echo "File is not an image.";
//     $uploadOk = 0;
//   }
// }
$time =date("Y-m-d-h-i-sa");

// Allow certain file formats
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg" ) {
  echo "jpg png jpeg mojaz hast";
  $uploadOk = 0;
}

// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
  echo "Upload nashod";
// if everything is ok, try to upload file

} else {

  if (move_uploaded_file($move, $target_file) ) {

  echo "<div class=dvs>". "File: ". basename( $_FILES["fileToUpload"]["name"]). " Upload shod !"."</div>";

  rename("$target_file",$target_dir.$time.".jpg");

  }

  else {
    echo "moshkeli dar upload shoma hast.";
  }
//   foreach(glob('jpg/*.jpg') as $filename1){
//     echo $filename1;
// }

}
?>