javascript not working, no errors

var xmlHttp
var layername
var url

function update(layer, part, pk, query) {
    alert ("update");
    if (part=="1") {
        alert ("part 1");
        url = "get_auction.php?cmd=GetAuctionData&pk="+pk+"&sid="+Math.random()
    } else if (part=="2") {
        alert ("part 2");
        url = "get_records.php?cmd=GetRecordSet&query="+query+"&sid="+Math.random()
    }
    xmlHttp=GetXmlHttpObject()
    if(xmlHttp==null) {
        alert("Your browser is not supported?")
    }
    xmlHttp.onreadystatechange = function() {
        if(xmlHttp.readyState==4 || xmlHttp.readyState=="complete") {
            document.getElementById(layer).innerHTML=xmlHttp.responseText
        } else if (xmlHttp.readyState==1 || xmlHttp.readyState=="loading") {
            document.getElementById(layer).innerHTML="loading"
        }
    };
    xmlHttp.open("GET",url,true)
    xmlHttp.send(null)
}

function GetXmlHttpObject() {
    var xmlHttp=null;
    try {
        xmlHttp = new XMLHttpRequest();
    } catch (e) {
        try {
            xmlHttp =new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {}
    }
    return xmlHttp;
}

function makewindows() {
    child1 = window.open ("about:blank");
    child1.document.write(<?php echo htmlspecialchars(json_encode($row2["ARTICLE_DESC"]), ENT_QUOTES); ?>));
    child1.document.close();
}

echo "<li><a href='#' onclick=update('Layer3','2','0','hello')'>Link 1</a></li>" .

<li><a href='#' onclick='update('Layer3','2','0','hello')'>Link 1</a></li>

echo '<li><a href="#" onclick="update('Layer3','2','0','hello')">Link 1</a></li>' . "n";

function update(layer, url) {
    var xmlHttp=GetXmlHttpObject(); //you have this defined elsewhere

    if(xmlHttp==null) {
        alert("Your browser is not supported?");
    }

    xmlHttp.onreadystatechange = function() {
        if(xmlHttp.readyState==4 || xmlHttp.readyState=="complete") {
            document.getElementById(layer).innerHTML=xmlHttp.responseText;
        } else if (xmlHttp.readyState==1 || xmlHttp.readyState=="loading") {
            document.getElementById(layer).innerHTML="loading";
        }

       //etc
    }

    xmlHttp.open("GET",url,true);
    xmlHttp.send(null);
}


function updateByPk(layer, pk) {
   url = "get_auction.php?cmd=GetAuctionData&pk="+pk+"&sid="+Math.random();
   update(layer, url);
}


function updateByQuery(layer, query) {
   url = "get_records.php?cmd=GetRecordSet&query="+query+"&sid="+Math.random();
   update(layer, url);
}

updateByPk('id_of_div', 2);

updateByQuery('id_of_div2', 'query');

<a href="#" onclick="updateByQuery('Layer3', 'hello');">Link 1</a>

<?php echo '<a href="#" onclick="updateByQuery('Layer3', ' . json_encode($query) . ');">Link 1</a>';

function myFunction(var1, var2, var3, var4){

myFunction('test1','test2');

if(null != var3){

child1.document.write(<?php echo htmlspecialchars(json_encode($row2["ARTICLE_DESC"]), ENT_QUOTES); ?>));

onclick=update('Layer3','2','0','hello')'>Link 1

onclick="update('Layer3','2','0','hello')">Link 1

onclick='update('Layer3','2','0','hello')'>Link 1

function update(layer, part, pk, query) {
   alert ("update");
   if (part=="1") {
      alert ("part 1");
      url = "get_auction.php?cmd=GetAuctionData&pk="+pk+"&sid="+Math.random()
   } else if (part=="2") {
      alert ("part 2");
      url = "get_records.php?cmd=GetRecordSet&query="+query+"&sid="+Math.random()
   }
   // and so on...
}