Multilanguage site works on localhost but not on the Internet - php

Question

I made a website, with 3 lang on it, and site works fine (localhost) but when I upload it, default lang is EN and whenever I change lang on the web, let's say from EN to FR, page goes on that lang in this case on FR and redirect me on home page and all text on site is on FR, that's ok, but after that, when I try to click on let's say about us, then on it's own change it back to default lang, and show me that page (about us) but on default lang...
Here is sample of code how it's look...
This is select.php and I include_once this file on every page...
<?php
session_start();
header('Cache-control: private'); // IE 6 FIX
if(isSet($_GET['lang']))
{
$lang = $_GET['lang'];
// register the session and set the cookie
$_SESSION['lang'] = $lang;
setcookie("lang", $lang, time() + (3600 * 24 * 30));
}
else if(isSet($_SESSION['lang']))
{
$lang = $_SESSION['lang'];
}
else if(isSet($_COOKIE['lang']))
{
$lang = $_COOKIE['lang'];
}
else
{
$lang = 'en';
}
switch ($lang) {
case 'en':
$lang_file = 'lang.en.php';
break;
case 'fr':
$lang_file = 'lang.fr.php';
break;
case 'de':
$lang_file = 'lang.de.php';
break;
default:
$lang_file = 'lang.en.php';
}
include_once 'lang/'.$lang_file;
This is lang.en.php...
$lang = array();
// menu
$lang['txt1'] = 'Home';
$lang['txt2'] = 'About Us';
$lang['txt3'] = 'Services';
$lang['txt4'] = 'Contact';
It's the same for other two languages...
and I simply put in index.php this...
<ul>
<li><em><b><?php echo $lang['txt1'];?></b></em></li>
<li><em><b><?php echo $lang['txt2'];?></b></em></li>
<li><em><b><?php echo $lang['txt3'];?></b></em></li>
<li><em><b><?php echo $lang['txt4'];?></b></em></li>
</ul>
When is on default lang, I can navigate fine, I can go on any page without problems, but problem is when I try to change site into other language(s),
let's say I'm on page www.example.com/about.php and I want to see this page on let's say FR, site will redirect me, on www.example.com/index.php?lang=fr (this is ok) and then I can see FR lang on site but only on home page, but when I try to go on www.example.com/about.php then site put back default lang, in this case EN...
Strange thing is that this script works fine on localhost...
Any idea why?
Update:
OUTPUT:
Array ( [lang] => lang value to put in session [something_1] => something value to put in session )
Array ( [lang] => new lang value but not set in session [something_1] => something value to put in session )
<?php
session_start();
$lang = "lang value to put in session";
$something = "something value to put in session";
$_SESSION['lang'] = $lang;
$_SESSION['something_1'] = $something;
print_r($_SESSION);
$lang = "new lang value but not set in session";
$something = "new something value but not set in session";
print_r($_SESSION);
PHP shouldn't change the second array
Array ( [lang] => lang value to put in session [something_1] => something value to put in session )
Array ( [lang] => new lang value but not set in session [something_1] => something value to put in session )
It should look like this:
Array ( [lang] => lang value to put in session [something_1] => something value to put in session )
Array ( [lang] => lang value to put in session [something_1] => something value to put in session )
Any idea why?

Answer 1

Be sure your files does NOT echo anything before settings the session
if your saving files as UTF , be sure it's UTF without BOM
disable display_errorsin ini file . try ini_set('display_errors',false);
i hope this helps , i encountered this problem many times .