var timerlen = 5;
var slideAniLen = 500;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        return;
}


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

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

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

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

        return;
}


function toggleSlide(the_div){
  if(document.getElementById(the_div).style.display == "none"){
    // div is hidden, so let's slide down
    slidedown(the_div);
  }else{
    // div is not hidden, so slide up
    slideup(the_div);
  }
}