php文件上传的简单实例

<?php
if ((($_files["file"]["type"] == "image/gif")
|| ($_files["file"]["type"] == "image/jpeg")
|| ($_files["file"]["type"] == "image/pjpeg"))
&& ($_files["file"]["size"] < 20000))
  {
  if ($_files["file"]["error"] > 0)
    {
    echo "return code: " . $_files["file"]["error"] . "<br />";
    }
  else
    {
    echo "upload: " . $_files["file"]["name"] . "<br />";
    echo "type: " . $_files["file"]["type"] . "<br />";
    echo "size: " . ($_files["file"]["size"] / 1024) . " kb<br />";
    echo "temp file: " . $_files["file"]["tmp_name"] . "<br />";

    if (file_exists("upload/" . $_files["file"]["name"]))
      {
      echo $_files["file"]["name"] . " already exists. ";
      }
    else
      {
      move_uploaded_file($_files["file"]["tmp_name"], "upload/" . $_files["file"]["name"]);//注释
      echo "stored in: " . "upload/" . $_files["file"]["name"];
      }
    }
  }
else
  {
  echo "invalid file";
  }
?>