Moving a file with html and php not working

'm trying to upload a file(actually move it from a directory to another) using PHP. The problem is, every time i load the html, after i select the file to upload and press submit, it redirects me to a page that actually saves my .php file instead of the file i'm trying to move. Do i need to give permissions to a program? I am working on ubuntu 14.04.

<html>
<body>

      <form action="upload_file.php" method="post" enctype="multipart/form-data">
      <label for="file">Filename:</label>
      <input type="file" name="file" id="file"><br>
      <input type="submit" name="submit" value="Submit">
</form>

</body>
</html>

And this is the PHP script:

<?php
     $allowedExts = array("gif", "jpeg", "jpg", "png");
     $temp = explode(".", $_FILES["file"]["name"]);
     $extension = end($temp);

     if ((($_FILES["file"]["type"] == "image/gif")
           || ($_FILES["file"]["type"] == "image/jpeg")
           || ($_FILES["file"]["type"] == "image/jpg")
           || ($_FILES["file"]["type"] == "image/pjpeg")
           || ($_FILES["file"]["type"] == "image/x-png")
           || ($_FILES["file"]["type"] == "image/png"))
           && ($_FILES["file"]["size"] < 20000)
           && in_array($extension, $allowedExts)) {
              if ($_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"],
                       "/home/laurentiu/Desktop/asd/" . $_FILES["file"]["name"]);
                       echo "Stored in: " . "/home/laurentiu/Desktop/asd/".
                             $_FILES["file"]["name"];
                  }
              }
} else {
    echo "Invalid file";
}
?>

Okay, now I've moved on a server.It prints:

Upload: launcher_arrow_ttb.png

Type: image/png

Size: 0.3017578125 kB

Temp file: /tmp/phpRanbFV

Stored in: /home/laurentiu/Desktop/asd/launcher_arrow_ttb.png

but nothing is uploaded. Moreover, when i var_dump the function it prints FALSE, so the function move_uploaded_file does not execute. Why i do not know...

Solution

This means your web server is not configured to run PHP files. Instead of executing PHP instruction in the file, it sends back the file like it would do with a plain text file.