var url = "";
var grid = "";

function showGalleryGrid(page) {
    xmlHttp = GetXmlHttpObject();
    if (xmlHttp == null) {
        alert("Your browser does not support AJAX!");
        return;
    }

    var ajaxurl = "";

    if (url.indexOf('?') == -1) {   //no querystring in url
        ajaxurl = url + "?pn=" + page;
    }
    else {  //querystring in url, append to querystring
        ajaxurl = url + "&pn=" + page;
    }
    
    xmlHttp.onreadystatechange = stateChanged;
    xmlHttp.open("GET", ajaxurl, true);
    xmlHttp.send(null);
}

function stateChanged() {
    if (xmlHttp.readyState == 4) {
        if (document.getElementById(grid)) {
            document.getElementById(grid).innerHTML = xmlHttp.responseText;
        }
    }
}

function GetXmlHttpObject() {
    var xmlHttp = null;
    try {
        // Firefox, Opera 8.0+, Safari
        xmlHttp = new XMLHttpRequest();
    }
    catch (e) {
        // Internet Explorer 5
        try {
            xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
        }
        // Internet Explorer 6
        catch (e) {
            xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
    }
    return xmlHttp;
}