Not getting data values with greek characters in Internet explorer

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Javascript

PHP

jQuery

Search is not working on IE, but works great on Chrome, Safari, Opera, Firefox.

it works great when it searches into database english characters on IE 10 but nothing shows as text when it searches into database to find greek characters. This happens only with IE.
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script type="text/javascript" src="js/textinputs_jquery.js"></script>
<script type="text/javascript" src="js/textinputs_jquery_src.js"></script>
<script>
$(document).ready(function(){

$("#comp_text").live('input paste',function(){
var str=document.getElementById("comp_text");
if (str.value.length <3){
return false;
}
var twidth=str.offsetWidth;
$('#txtHint').width(twidth);
$('#txtHint').load('gethint.php?q='+str.value);
});
$(".add").submit( function(){
if($('#company').length){
return true;
}else{
alert("");
return false;
}
});
});

function showHint(str)
{
if (str.length==0)
{
document.getElementById("txtHint").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp. önreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","gethint.php?q="+str,true);
xmlhttp.send();
}


function set_val(str, company){
document.getElementById('comp_text').value= str;
document.getElementById('txtHint').innerHTML="";
document.getElementById("customer_place").innerHTML='<input type="hidden" id="company" value="'+company+'">';
}
function cust_control(){

if (document.getElementByName('company')){
alert ("");
return false;
}else
return true;
}

</script>
<form method=\"post\" name=\"addn\" class=\"add\" action=\"do_insert.php\">
<input type="text" id="comp_text" önkeyup="showHint(this.value)" name="company" size="20" style="text-align: center; font-size: 13px;"/>
<div id="txtHint"></div>
<div id="customer_place"></div>
</form>





and gethint.php ...

$q=$_GET["q"];
$response='';

$query="SELECT uid, company FROM users where company like '".$q."%' and userid='$userid' order by company";
mysql_query("set character set 'utf8'");
$result=mysql_query($query);

if (mysql_num_rows($result) > 0) {
$response.='<table>';
    while ($row=mysql_fetch_array($result)){
$response.='<tr><td önclick="set_val(\''.$row['company'].'\', \''.$row['uid'].'')">'.$row['company'].'</td></tr>';
    }
$response.='</table>';  
echo $response;
}else{
}