Jquery Ajax no response - php

Question

When I try to get the response from a php file using Jquery ajax, I just get (an empty string) (Accdg. to Firebug console using console.log(data))
Here's the Html code:
<form action="test.php" method="POST" id="ajax">
<input type="text" name="field" />
<input type="submit" value="submit" name="submit" />
</form>
Here's the Jquery code:
$('#ajax').submit(function(e) {
e.preventDefault();
$.ajax({
type: 'POST',
data: $(this).serialize(),
url: 'test.php',
cache: false,
success: function(data) {
alert(data);
}
});
return false;
});
And the PHP code:
if ($_POST['submit'] == "submit")
{
echo 'Got your request';
}
Just basic. What frustrates me is that it's straightforward, I've done some research and still it doesn't work. I also want it to be as simple as possible.
Please enlighten me.

Answer 1

Don't check to see if you're in a POST situation by checking for fieldnames. That's incorrect - you might change your client-side form names and forget to update the PHP check.
The 100% reliable method is to use:
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
echo "Got your request";
}
However, since you just want to see if the server got pinged at all by your ajax call, why not do:
<?php
echo "Got your ", $_SERVER['REQUEST_METHOD'], " request";
Which'd just return Got your POST request or Got your GET request, etc...
As well, check your server log (or use HTTPFOX/Firebug Net tab, etc...) to see if that ajax request is actually going out and being received by the server.

Answer 2

The problem with the serialize() method is that it doesn't include the name of the button parameter which you use in your php script (submit=submit parameter). It doesn't do it because it doesn't know which button was clicked. This parameter is only included by the browser when you submit the form normally.
So one possibility is to manually attach this parameter as query string parameter:
url: 'test.php?submit=submit',
and in your PHP script:
if ($_GET['submit'] == "submit")
{
echo 'Got your request';
}