ajax načítanie z databáze

<script language="javascript1.3" src="ajax.js" ></script>
<a href="javascript:jah('priklad.php?a=10&b=5','change');">skuska</a>
<div id="change">Obsah načítaného súboru</div>

function jah(url,target) {
    document.getElementById(target).innerHTML = 'posielam...';
    if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
        req.onreadystatechange = function() {jahDone(target);};
        req.open("GET", url, true);
        req.send(null);
    } else if (window.ActiveXObject) {
        req = new ActiveXObject("Microsoft.XMLHTTP");
        if (req) {
            req.onreadystatechange = function() {jahDone(target);};
            req.open("GET", url, true);
            req.send();
        }
    }
}    
function jahDone(target) {
    if (req.readyState == 4) {
        if (req.status == 200) {
            results = req.responseText;
            document.getElementById(target).innerHTML = results;
        } else {
            document.getElementById(target).innerHTML="jah error:\n" +
                req.statusText;
        }
    }
}