var timerlen = 5;
var slideAniLen = 250;

var timerID = new Array();
var startTime = new Array();
var obj = new Array();
var endHeight = new Array();
var moving = new Array();
var dir = new Array();

function slidedown(objname) {
    if (moving[objname])
        return;

    if (document.getElementById(objname).style.display != "none")
        return; // cannot slide down something that is already visible

    moving[objname] = true;
    dir[objname] = "down";
    startslide(objname);
}

function slideup(objname) {
    if (moving[objname])
        return;

    if (document.getElementById(objname).style.display == "none")
        return; // cannot slide up something that is already hidden

    moving[objname] = true;
    dir[objname] = "up";
    startslide(objname);
}

function startslide(objname) {
    obj[objname] = document.getElementById(objname);

    endHeight[objname] = parseInt(obj[objname].height);
    startTime[objname] = (new Date()).getTime();

//    if (dir[objname] == "down") {
//        obj[objname].style.height = "1px";
//    }

    obj[objname].style.display = "block";

    timerID[objname] = setInterval('slidetick(\'' + objname + '\');', timerlen);
}

function slidetick(objname) {
    var elapsed = (new Date()).getTime() - startTime[objname];

    if (elapsed > slideAniLen)
        endSlide(objname)
    else {
        var d = Math.round(elapsed / slideAniLen * endHeight[objname]);
        if (dir[objname] == "up")
            d = endHeight[objname] - d;

        obj[objname].height = d + "px";
    }

    return;
}

function endSlide(objname) {
    clearInterval(timerID[objname]);

    if (dir[objname] == "up")
        obj[objname].style.display = "none";

    obj[objname].height = endHeight[objname] + "px";

    delete (moving[objname]);
    delete (timerID[objname]);
    delete (startTime[objname]);
    delete (endHeight[objname]);
    delete (obj[objname]);
    delete (dir[objname]);

    return;
}