I created a simple comment wall that submits using ajax.

Using javascript i collect user input:

var sharetxt =  encodeURIComponent(document.getElementById("cw_share_txt".value);
then pass it to a php page, on the php page, i collect the passed data:

$text=nl2br(htmlentities(trim($_POST["txt"])));
Encoding of the php page above:

header("Content-Type: text/xml; charset=utf-8";
My problem is that

the wall doesnt still support multi languages (displays as ? and causes my xml not to work)

i still problems with some special characters (displays as � or ?)

What am i not doing right? please assist

try using the other charset, or remove it entirely, maybe you are doing it twice

@sayhi2ay, which other charset supports multi languages?

try

charset=iso-8859-1

sayhi2ay:

try

charset=iso-8859-1

that was what i was going to say too.
For most of my ajax-driven apps, i usually boot the page with
header("Content-Type: text/xml; charset=iso-8859-1";