var preload = new Image();
preload.src = "img/nav/rub1-exam-on.gif";
preload = new Image();
preload.src = "img/nav/rub2-spec-on.gif";
preload = new Image();
preload.src = "img/nav/rub3-sites-on.gif";
preload = new Image();
preload.src = "img/nav/rub4-infos-on.gif";
preload = new Image();
preload.src = "img/nav/rub5-contact-on.gif";

preload = new Image();
preload.src = "img/nav/srub-exam-sr1-on.gif";
preload = new Image();
preload.src = "img/nav/srub-exam-sr2-on.gif";
preload = new Image();
preload.src = "img/nav/srub-exam-sr3-on.gif";
preload = new Image();
preload.src = "img/nav/srub-exam-sr4-on.gif";
preload = new Image();
preload.src = "img/nav/srub-exam-sr5-on.gif";
preload = new Image();
preload.src = "img/nav/srub-exam-sr55-on.gif";
preload = new Image();
preload.src = "img/nav/srub-exam-sr6-on.gif";
preload = new Image();
preload.src = "img/nav/srub-exam-sr7-on.gif";
preload = new Image();
preload.src = "img/nav/srub-exam-sr8-on.gif";

preload = new Image();
preload.src = "img/nav/srub-2-spec-dr0-on.gif";
preload = new Image();
preload.src = "img/nav/srub-2-spec-dr1-on.gif";
preload = new Image();
preload.src = "img/nav/srub-2-spec-dr2-on.gif";
preload = new Image();
preload.src = "img/nav/srub-2-spec-dr3-on.gif";
preload = new Image();
preload.src = "img/nav/srub-2-spec-dr4-on.gif";
preload = new Image();
preload.src = "img/nav/srub-2-spec-dr5-on.gif";
preload = new Image();
preload.src = "img/nav/srub-2-spec-dr6-on.gif";
preload = new Image();
preload.src = "img/nav/srub-2-spec-dr7-on.gif";

preload = new Image();
preload.src = "img/nav/srub-3-irm-on.gif";
preload = new Image();
preload.src = "img/nav/srub-3-scan-on.gif";
preload = new Image();
preload.src = "img/nav/srub-3-mous-on.gif";
preload = new Image();
preload.src = "img/nav/srub-3-drav-on.gif";

preload = new Image();
preload.src = "img/nav/srub-infos-sr1-on.gif";
preload = new Image();
preload.src = "img/nav/srub-infos-sr2-on.gif";
preload = new Image();
preload.src = "img/nav/srub-infos-sr3-on.gif";

var visibleValue = "visible";
var timer = 0;
var nbMenu = 4;

function getDivStyleByDivId(divId)
{
    if (document.layers)
    {
        visibleValue = "show";
        return document[divId];
    }
    else if (document.all)
        return document.all[divId].style;
    else if (document.getElementById)
        return document.getElementById(divId).style;
}

function showMenu(divId, top, left)
{
    clearTimeout(timer);
    closeAll();
    var divStyle = getDivStyleByDivId(divId);
    divStyle.visibility = visibleValue;
    divStyle.top = top + "px";
    divStyle.left = left + "px";
}

function hideMenu(divId)
{
    var divStyle = getDivStyleByDivId(divId);
    divStyle.visibility = "hidden";
}

function menuOver()
{
    clearTimeout(timer);
}

function menuOut()
{
    timer = setTimeout("closeAll()", 250);
}

function closeAll()
{
    for (i = 1; i <= nbMenu; i++)
    {
        hideMenu("menu" + i);
    }
}