Jquery Ajax Data Post Problem in PHP - php

Question

I am using jquery's AJAX in my project. Today, I used it somewhere else with all same themethods but it doesn't work.
Is there something wrong with my script?
HTML:
<a class='btn edit_receipe_btn' id='myreceipe-52'>Edit</a>
JQuery:
(Click function works. When I put alert(instance) after var instance line, it works)
$(document).ready(function(){
$('.edit_receipe_btn').click(function(){
var instance = $(this).attr('id');
var dataString = 'process=userReceipeEdit&instance='+instance;
$.ajax({
type: 'POST',
url: 'ajax/ajaxs.php',
data: dataString,
cache: false,
success: function(msg) {
alert(msg);
}
});
});
});
PHP:
$prcs = $_POST['process'];
if($prcs=='userReceipeEdit'){
$instance = $_POST['instance'];
return $instance;
}
It appears the problem is in the PHP. What am I doing wrong?

Answer 1

Is that the entire PHP page? if so, you should echo instead of return

Answer 2

As Jasper De Bruijn notified me, the problem was in my php script. I should use echo instead of return:
Wrong usage:
$prcs = $_POST['process'];
if($prcs=='userReceipeEdit'){
$instance = $_POST['instance'];
return $instance;
}
Correct usage:
$prcs = $_POST['process'];
if($prcs=='userReceipeEdit'){
$instance = $_POST['instance'];
echo $instance;
}

Answer 3

Two things, output the error and check to make sure instance is not undefined.
Output the error like this:
$('.edit_receipe_btn').click(function(){
var instance = $(this).attr('id');
var dataString = 'process=userReceipeEdit&instance='+instance;
$.ajax({
type: 'POST',
url: 'ajax/ajaxs.php',
data: dataString,
cache: false,
success: function(msg) {
alert(msg);
},
error: function(response, status, error)
{
alert(response.responseText);
alert(status);
alert(error);
}
});
});

Answer 4

I think you have formed this POST like a get, not sure why. Try doing this in JS:
var dataString =
{
"process" : "userReceipeEdit",
"instance" : instance
};