UTf-8 fetch title an description problem

Hello ,

i have an .js file to fetch title and description from another site have utf8 charset and my site also have utf8 charset

it fetch english character well but arabic or turki character it appear such that ????????? ???? ????????

.js content

function request_videoinfo()
{
	if (!fetch_object('videourl').value)
	{
		return false;
	}

	YAHOO.util.Connect.asyncRequest("POST", "video.php?do=videoinfo", {
		success: handel_videoinfo,
		failure: vBulletin_AJAX_Error_Handler,
		timeout: 15000
	}, SESSIONURL + 'securitytoken=' + SECURITYTOKEN + "&url=" + PHP.urlencode(fetch_object('videourl').value) + "&wysiwyg=" + vB_Editor[editor_id].wysiwyg_mode);

	fetch_object('videoajaxbutton').value = vbphrase['requesting_information_please_wait'];
	fetch_object('videoajaxbutton').disabled = true;

	return false;
}

function handel_videoinfo(ajax)
{
	if (ajax.responseXML)
	{
		// check for error first
		var error = ajax.responseXML.getElementsByTagName('error');
		if (error.length)
		{
			fetch_object('thumbnail').setAttribute('src', '');
			fetch_object('thumbnail_border').style.display = 'none';
			alert(error[0].firstChild.nodeValue);
		}
		else
		{
			try
			{
				var description = ajax.responseXML.getElementsByTagName('description')[0].firstChild.nodeValue;
				vB_Editor[editor_id].insert_text(description);
			}
			catch (e)
			{
			}

			try
			{
				var title = ajax.responseXML.getElementsByTagName('title')[0].firstChild.nodeValue;
				fetch_object('videotitle').value = title;
			}
			catch (e)
			{
			}

			try
			{
				var videothumbnailpath = ajax.responseXML.getElementsByTagName('thumbnailpath')[0].firstChild.nodeValue;
				fetch_object('thumbnail').setAttribute('src', videothumbnailpath);
				fetch_object('thumbnail_border').style.display = '';
			}
			catch (e)
			{
			}
		}
	}
	fetch_object('videoajaxbutton').value = vbphrase['request_videoinfo_from_service'];
	fetch_object('videoajaxbutton').disabled = false;
}