var timerlen = 8;
var slideAniLen = 400;

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].style.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].style.height = d + "px";
  }

  return;
}

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

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

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

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

  return;
}

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