function hoverIE() {
    var LI = document.getElementById("navi").firstChild;
    do {
        if (sucheUL(LI.firstChild)) {
            LI.onmouseover=einblenden; LI.onmouseout=ausblenden;
        }
        LI = LI.nextSibling;
    }
    while(LI);
}

function sucheUL(UL) {
    do {
        if(UL) UL = UL.nextSibling;
        if(UL && UL.nodeName == "UL") return UL;
    }
    while(UL);
    return false;
}

function einblenden() {
    var UL = sucheUL(this.firstChild);
    UL.style.display = "block"; UL.style.backgroundColor = "#c6060c";
}
function ausblenden() {
    sucheUL(this.firstChild).style.display = "none";
}

function menu_hover (id, img) {
    document.getElementById(id).src=img;
}

function preloader() 
{
    // set image list
    images = new Array();
    images[0]="files/images/menu/home_hover.png"
    images[1]="files/images/menu/about_hover.png"
    images[2]="files/images/menu/research_hover.png"
    images[3]="files/images/menu/tracking_hover.png"
    images[4]="files/images/menu/education_hover.png"
    images[5]="files/images/menu/publications_hover.png"
    images[6]="files/images/loading.gif"
    images[7]="files/images/invisible.gif"
    images[8]="files/images/zoom.gif"
    // start preloading
    for (i=0; i < images.length; i++) {
        var imageObj = new Image();
        imageObj.src = images[i];
    }
}

if(window.navigator.systemLanguage && !window.navigator.language) { window.onload = hoverIE, preloader; }
else window.onload = preloader;