PHP $_POST not working? [duplicate]

Question

I have the simplest form possible and all I want to do is echo whatever is written in text box.

HTML:

<form action="" method="post">
  <input type="text" name="firstname">
  <input type="submit" name="submit" value="Submit">
</form>

PHP:

if(isset($_POST['submit'])){
  $test = $_POST['firstname'];
  echo $test;
}

The problem is it's not working on my server (it works on another server). Does anyone has an idea what could be wrong? There are other forms on the server and are working fine.

Answer 1

I had something similar this evening which was driving me batty. Submitting a form was giving me the values in $_REQUEST but not in $_POST.

Eventually I noticed that there were actually two requests going through on the network tab in firebug; first a POST with a 301 response, then a GET with a 200 response.

Hunting about the interwebs it sounded like most people thought this was to do with mod_rewrite causing the POST request to redirect and thus change to a GET.

In my case it wasn't mod_rewrite to blame, it was something far simpler... my URL for the POST also contained a GET query string which was starting without a trailing slash on the URL. It was this causing apache to redirect.

Spot the difference...

Bad: http://blah.de.blah/my/path?key=value&otherkey=othervalue
Good: http://blah.de.blah/my/path/?key=value&otherkey=othervalue

The bottom one doesn't cause a redirect and gives me $_POST!

Answer 2

A few thing you could do:

1. Make sure that the "action" attribute on your form leads to the correct destination.
2. Try using $_REQUEST[] instead of $_POST, see if there is any change.

3. [Optional] Try including both a 'name' and an 'id' attribute e.g.

   <input type="text" name="firstname" id="firstname">
   

4. If you are in a Linux environment, check that you have both Read/Write permissions to the file.

In addition, this link might also help.

EDIT:

You could also substitute

<code>if(isset($_POST['submit'])){</code>

with this:

<code>if($_SERVER['REQUEST_METHOD'] == "POST"){ </code>

This is always the best way of checking whether or not a form has been submitted

Answer 3

Dump the global variable to find out what you have in the page scope:

var_dump($GLOBALS);

This will tell you the "what" and "where" regarding the data on your page.

Answer 4

I also had this problem. The error was in the htaccess. If you have a rewrite rule that affects the action url, you will not able to read the POST variable.

To fix this adding, you have to add this rule to htaccess, at the beginning, to avoid to rewrite the url:

RewriteRule ^my_action.php - [PT]