Bir tane ziyaretçi defteri buldum Ajax ile çalışan fakat Türkçe karakter hatası veriyor

kodları şunlar:

function ajax(method,strURL,variable,value,sid) {
    var xmlHttpReq = false;
    var self = this;

    // Mozilla/Safari
    if (window.XMLHttpRequest) {
        self.xmlHttpReq = new XMLHttpRequest();
    }
    // IE
    else if (window.ActiveXObject) {
        self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
    }
    self.xmlHttpReq.open(method, strURL, true);
    self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    
    self.xmlHttpReq.onreadystatechange = function() {
        
    if(value == 'signgb' ){
    document.signgb.signbutton.disabled = true;
    document.getElementById('signdiv').innerHTML = '<center><img src="images/loading.gif"><br><br><b>'+loadtext+'...</b><br></center>';
            
    }else{
    document.getElementById('entries').innerHTML = '<center><br><br><br><br><img src="images/loading.gif"><br><br><b>'+loadtext+'...</b><br><br><br></center>';
    }
    
       if (self.xmlHttpReq.readyState == 4) {
            if(value == 'signgb' ){
            updatepage(self.xmlHttpReq.responseText,'signgb');
            }else{
            updatepage(self.xmlHttpReq.responseText,'page');
            }
       }
        
    }
    
    if (value == 'signgb'){
    name=document.signgb.name.value;
    email=document.signgb.email.value;
    homepage=document.signgb.homepage.value;
    message=document.signgb.message.value;
    
    self.xmlHttpReq.send('dosign=yes&name=' + name + '&email=' + escape(email) + '&homepage=' + escape(homepage) + '&message=' + message);
    }else{
    self.xmlHttpReq.send(escape(variable) + '=' + escape(value) + '&sid=' + sid);
    }
    
}



function updatepage(str, value){
    
    //if (self.xmlHttpReq.readyState == 4) {
    if (value == 'signgb'){
    document.getElementById("signdiv").innerHTML = str;
    showdiv('signdiv');
    document.signgb.signbutton.disabled = false;
    }else{
    document.getElementById("entries").innerHTML = str;
    showdiv('entries');
    }
    //}
}

function hidediv(id) {
    //safe function to hide an element with a specified id
    if (document.getElementById) { // DOM3 = IE5, NS6
        document.getElementById(id).style.display = 'none';
    }
    else {
        if (document.layers) { // Netscape 4
            document.id.display = 'none';
        }
        else { // IE 4
            document.all.id.style.display = 'none';
        }
    }
    if(id == 'signform'){
    showdiv('entries');
    hidediv('signdiv');
    }
}

function showdiv(id) {
    //safe function to show an element with a specified id
          
    if (document.getElementById) { // DOM3 = IE5, NS6
        document.getElementById(id).style.display = 'block';
    }
    else {
        if (document.layers) { // Netscape 4
            document.id.display = 'block';
        }
        else { // IE 4
            document.all.id.style.display = 'block';
        }
    }
    if(id == 'signform')
    hidediv('entries');
}
  function smiley(s){
  document.signgb.message.value = document.signgb.message.value + s;
  document.signgb.message.focus();
}

biraz uğraştım olmadı

nasıl düzeltebiliriz acaba.