<?PHP

$uploaddir = "users"; // set this to your upload directory make sure to set permissions to 777

if ($_FILES['File']) { // if a file has been selected
     echo "File name:" . $_FILES['File']['name'] . "<br />";
     echo "File Size:" . $_FILES['File']['size'] . "<br />";
     echo "File Type:" . $_FILES['File']['type'] . "<br />";
     echo "Error Code:" . $_FILES['File']['error'] . "<br />";
     
     // validate the file
     $input_errors = array();
     
     $allowed_ext = "jpg, gif, png, txt"; // file extensions that can be uploaded
     $max_size = "50000"; // in bytes i.e. 50000 = 50KB
     $max_height = "300"; // height in pixels (leave empty if not uploading images)
     $max_width = "300"; // width in pixels (leave empty if not uploading images)

     // Check Entension
     $extension = pathinfo($_FILES['File']['name']);
     $extension = $extension[extension];
     $allowed_paths = explode(", ", $allowed_ext);
     for($i = 0; $i < count($allowed_paths); $i++) {
          if ($allowed_paths[$i] == "$extension") {
               $continue = "TRUE";
          }
     }

     if ($continue == "TRUE") {
     
          // Check File Size
           if($_FILES['File']['size'] > $max_size) {
               $input_errors[] = "The file is bigger than the maximum allowed size";
           }

          // Check Height & Width
           if ($max_width && $max_height) {
               list($width, $height, $type, $w) = getimagesize($_FILES['File']['tmp_name']);
               if($width > $max_width || $height > $max_height) {
                    $input_errors[] = "The image height/width is too big";
               }
           }
          
     } else {
          $input_errors[] = "That type of file cannot be uploaded";
     }
     
     if (count($input_errors) == 0) {
          if (move_uploaded_file($_FILES['File']['tmp_name'], $uploaddir.'/'.$_FILES['File']['name'])) {
           echo "Uploaded file Successfully <p />";
          } else {
         echo "Could not copy file to location <p />";
          }
     } else {
      echo "The following errors occured: <p />";
          echo "<ul>";
          for ($j=0; $j < count($input_errors); $j++) {
               echo "<li>" . $input_errors[$j] . "</li>";
      }
          echo "</ul>";
     }
}

// display form whatever the result i.e. if user wants to upload more than one file

echo "Upload a file to the server";
echo <<< FOO
     <form action="upload.php" method="post" enctype="multipart/form-data">
     <input type=file name="File" size="20"><br />
     <input type=submit name="Upload" value="Upload">
     </form>
FOO;

?>