How to programmatically post extended ascii character to facebook post?

I'm trying to post special characters to facebook feed, but the characters shown in the facebook post doesn't show as I intended.

$tmp = "αвнιjτυz";

//This code works as I intended, showing "αвнιjτυz" on facebook post
$facebook->api('/me/feed', 'POST', array('message' => $tmp));

//I expe开发者_开发知识库ct the displayed text in facebook post will be 'вн' but it shows strange characters instead
$facebook->api('/me/feed', 'POST', array('message' => substr($tmp, 1, 2)));

Any ideas why this happens and how to tackle this problem?

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I'm guessing this is unicode that you're working in. If so substr() won't work with unicode characters as they're represented with multiple bytes, you will need to use the mb_substr() function instead.

$facebook->api('/me/feed', 'POST', array('message' => mb_substr($tmp, 1, 2)));

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This is an old question, but missing the follow-up to Martin's question (and solution to question).

You should set the Content-Type of both the html and php to UTF-8. So at the beginning of the php code:

header('Content-Type: text/html; charset=utf-8');

And with the html:

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">