function fadein(item) {
    item.style.opacity = 1;
}

function fadeout(item) {
    item.style.opacity = 0.5;
}

var pageWidth = 622;
function forward() {
    var currentPos = $("#thumblist").css("margin-left");
    currentPos = (currentPos == "auto") ? 0 : currentPos.replace("px", "") * 1;
    if (currentPos <= ($("#thumblist table").length - 1) * -pageWidth) {
        currentPos = 0;
    } else {
        currentPos -= pageWidth;
    }
    currentPos += "px";
    $("#thumblist").animate({ marginLeft: currentPos }, 500);
}

function back() {
    var currentPos = $("#thumblist").css("margin-left");
    currentPos = (currentPos == "auto") ? 0 : currentPos.replace("px", "") * 1;
    if (currentPos >= 0) {
        currentPos = ($("#thumblist table").length - 1) * -pageWidth;
    } else {
        currentPos += pageWidth;
    }
    currentPos += 'px';
    $("#thumblist").animate({ marginLeft: currentPos }, 500);
}

function closefoto() {
    var div = document.getElementById("foto");
    div.style.display = (div.style.display == "block") ? "none" : "block";
}

function showFoto(img) {
    var div = document.getElementById("foto");
    if (div) {
        if (div.innerHTML.indexOf(img) > -1 && div.style.display == "block") {
            div.style.display = "none";
        } else {
            div.innerHTML = "<img src=\"" + img + "\" alt=\"klik om te sluiten\" id=\"fotoview\" />";
            div.style.display = "block";
        }
        //div.style.zIndex = 11;
    }
}

function scrollfotonav(direction) {
    var increment = 28;
    var steps = 4;
    if (direction == "up") increment *= -1;
    //document.getElementById("thumbs").scrollTop += increment * steps;
    for (i = 0; i < steps; i++) {
        setTimeout("document.getElementById(\"thumbs\").scrollTop += " + increment + ";", i * 50);
    }
}

function getWistUDat(id, div) {
    var url = "/ajax/default.aspx?o=wistudat&id=" + id;
    makeRequest(url, showNieuws, div);
}

function getNieuws(id, div) {
    var url = "/ajax/default.aspx?o=nieuws&id=" + id;
    makeRequest(url, showNieuws, div);
}

function showNieuws(response, eventargs) {
    var div = document.getElementById(eventargs);
    if (div) div.innerHTML = response;
}

function getProject(id, div) {
    var url = "/ajax/?o=project&id=" + id;
    makeRequest(url, showProject, div);
}

function showProject(response, eventargs) {
    var div = document.getElementById(eventargs);
    if (div) div.innerHTML = response;
}

//make http_request
function makeRequest(url, handler, eventargs) {
    window.status = 'Loading'
    document.body.style.cursor = 'progress';
    var http_request = false;

    // Mozilla, Safari,...
    if (window.XMLHttpRequest) {
        http_request = new XMLHttpRequest();
        if (http_request.overrideMimeType) {
            http_request.overrideMimeType('text/xml');
        }
    } else if (window.ActiveXObject) {
        // IE
        try {
            http_request = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
            try {
                http_request = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) { }
        }
    }

    if (!http_request) {
        alert('Giving up :( \nCannot create an XMLHTTP instance\n\nTry downloading a newer version of your browser');
        return false;
    }

    http_request.onreadystatechange = function() { return alertContents(http_request, url, handler, eventargs); };
    http_request.open('GET', url, true);
    http_request.send(null);
}

//monitor request, trigger handling when complete
function alertContents(http_request, url, handler, eventargs) {

    if (http_request.readyState == 4) {
        cursor = 'normal';
        if ((http_request.status == 200) || (http_request.status == 0)) {
            document.body.style.cursor = 'auto';
            window.status = 'Done'

            //if (pageTracker) pageTracker._trackPageview(url);
            handler(http_request.responseText, eventargs);
        } else {
            alert('There was a problem with the request using url\n\'' + url + '\'\nResponse: \n\n' + http_request.responseText);
            return false;
        }
    }
}