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].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;
}