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(mydiv){
        if(moving[mydiv])
                return;

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

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

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

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

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

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

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

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

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

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

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

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

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

        return;
}

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

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

        obj[mydiv].style.height = endHeight[mydiv] + "px";

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

        return;
}