Ajax chat problém s češtinou

<?include("config.php");?>
<script type="text/javascript" src="chatclient.js"></script>
<script language="JavaScript">
<!--
function setsmiley(what){
	tmp=document.getElementById("mytext");
    tmp.value = tmp.value+" "+what+" ";
    tmp.focus();
}
//-->
</script>
<table><tr><td><div id="chatpane"><div id="chatbuffer"></div></div></td></tr></table>
<table><tr><td><input style="width: 190px;" id="mytext" name="mytext" type="text" onFocus="textFocus=true" onBlur="textFocus=false"></td></tr></table> 
<script type="text/javascript">startChat();</script>

<script>
  	var isFirefox;
		var isIE;
		var timeout;
		var pingtimeout;
		var textFocus   = true;
		var starsadded  = false;
		var timedout    = 0;
		var requestsent = 0;
		var chatsent	= 0;
		var pingRate	= 1000 * 30;
		var refreshRate = 1000 * 2;
		
		var t = 0;
		var update_period = 3;
		var throttle_back = 60;
		var lastpost = 0;
		
		function getAjax() {
          var xmlhttp;
          
          if (!xmlhttp && typeof XMLHttpRequest != 'undefined') {
            try {
              xmlhttp = new XMLHttpRequest();
            } catch (e) {
              xmlhttp = false;
            }
		  }
          return xmlhttp;
        }

		function sniff() {
		
			var ff = "Netscape";
			var ie = "Microsoft Internet Explorer";
			
			isFirefox = ( navigator.appName == ff );
			isIE = (navigator.appName == ie ); 
		}

		function captureReturn( event )
		{
			if( isIE ) {
			
				event = window.event;
			}
			if( event.keyCode == 13 ) {
				postText();
					
				if( isIE ) {
				
					event.returnValue = false;
					
				} else {
				
					event.preventDefault();
				
				}
			}
			
			charCount();
		}

		function scrollChatPane()
		{
			pane = document.getElementById( "chatpane" );
			
			while( pane.scrollTop < pane.scrollHeight - pane.offsetHeight )
			{
				pane.scrollTop = pane.scrollTop + 10;
			}
		}

		function showLoadScreen()
		{
			var loading = "<div style=\"text-align:center;\"><h4><img src=styles/loader.gif><br>Načítání chatu...</h4></div>";
			
			chat = document.getElementById( "chatbuffer" );
			
			chat.innerHTML = loading;
		}

		function setTimers()
		{
			timeout = window.setTimeout( "fetch()", refreshRate );
		}

		function fetch()
		{
			window.clearTimeout( timeout );
			fetchBufferText();
			if(t++ % update_period) { 
			  fetchUserList();
			}    
			
			if( t - lastpost > throttle_back ) {
			  refreshRate = 2000;
			  update_period = 2;
			} else {
			  refreshRate = 1000;
			  update_period = 3;
			}
			
			if( timedout != 1 ) { setTimers(); }
		}

		function fetchUserList()
		{		
	    fetchBufferText();				
		}
		
		function fetchBufferText()
		{

			url = 'buffertext.php';
			req = getAjax();
			
			req.onreadystatechange = function(){
			
				if( req.readyState == 4 && req.status == 200 ) {
				
					obj = document.getElementById( "chatbuffer" );
					obj.innerHTML = req.responseText;
					scrollChatPane();
				}
			}
			
			req.open( 'GET', url , true );
			req.send( null );
		}
		
		function postText()
		{
			chatbox = document.getElementById( "mytext" );
			chat = escape(chatbox.value);
			chatbox.value = '';
			if(chat.length == 0 ) {return; }

			url = 'posttext.php?t=' + chat ;
			
			req = getAjax();
			
			req.onreadystatechange = function(){
			
				if( req.readyState == 4 && req.status == 200 ) {
				
					fetch();
				}
			
			}
			
			req.open( 'GET', url, true );
			req.send( null );
			
			lastpost = t;
		}
		
		function startChat()
		{
			sniff();
			showLoadScreen();
			setTimers();

			
			if( isFirefox ) {
				mytext = document.getElementById( "mytext" );
			}
			mytext.focus();
			mytext.onkeypress = captureReturn;
		}
</script>

<?
include("config.php");
session_register("idowner");
$idonline2=$idowner;
$chattext=$_GET['t'];
$chat="chatperson";
$nametable="$chat$myid$idonline2";
$nametable2="$chat$idonline2$myid";
$sloupec1="owner";
$sloupec2="date";
$sloupec3="text";
$sloupec4="status";
$status="no";
$date=StrFTime("%d.%m.%Y %H:%M:%S", Time());
MySQL_Query("INSERT INTO $nametable($sloupec1,$sloupec2,$sloupec3,$sloupec4) VALUES('".$myid."','".$date."','".$chattext."','".$status."')");
MySQL_Query("INSERT INTO $nametable2($sloupec1,$sloupec2,$sloupec3,$sloupec4) VALUES('".$myid."','".$date."','".$chattext."','".$status."')");
$chatperson="chatperson_my";
$chatpersontable="$chatperson$idonline2";
$numzero="0";
$numtwo="2";
mysql_query("UPDATE $chatpersontable SET status = '$numtwo' WHERE status = '$numzero' and owner='$myid'");
?>