// JavaScript Document

var navInterval = null;
var loadBuffer = null;
var element = null;
var dropSpeed = 0;
var maxHeight = 0;
var maxWidth = 0;
var initHeight = 0;
var width = 0;
var height = 0;

function dropDown(elem, dropS, maxH, maxW)
{	
	initHeight = 0;
	element = document.getElementById(elem);
	element.style.visibility = "visible";
	dropSpeed = dropS;
	maxHeight = maxH;
	maxWidth = maxW;
	setWidth();
	setPos();
	window.onresize = setPos;
	loadBuffer = setTimeout(startOpen, 200);
	
	function startOpen()
	{
		navInterval = setInterval("dropInt()", 4);	
	}
}

function dropInt()
{
	if (initHeight < maxHeight) 
		initHeight += maxHeight/dropSpeed;
	else  {
		initHeight = maxHeight;
		clearInterval(navInterval);
	}
	element.style.height = initHeight + "px";
	element.style.top = (height/2 - initHeight/2) + "px";
}

function setWidth()
{
	width = window.document.body.clientWidth;
	height = document.documentElement.clientHeight;	
}

function setPos()
{
	setWidth();
	element.style.top = (height/2 - initHeight/2) + "px";
	element.style.left = (width/2 - maxWidth/2) + "px";	
}

function visible(holderID, level)
{
	document.getElementById(holderID).style.opacity = level;
	document.getElementById(holderID).style.filter = 'alpha(opacity=' + (level * 100) + ')';
    document.getElementById(holderID).style.MozOpacity=level;
}