var timerlen = 15;
var slideAniLen = 1000;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        return;
}

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

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

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

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

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