function createHeader()
{
	var oLink = document.createElement("link") 
	oLink.href = "http://portalnav.parcye.com/portalnav.css"; 
	oLink.rel = "stylesheet"; 
	oLink.type = "text/css"; 
	document.body.appendChild(oLink); 

	var iFulLWidth = (document.getElementById&&!document.all) ? this.innerWidth : document.documentElement.clientWidth;
	
	var oDl = document.createElement("dl");
	oDl.id = "portalnav";
	oDl.style.width = iFulLWidth + 'px';

	var oHeader = document.createElement("dt");
	oHeader.id = "portalnav_head";
	// oHeader.style.width = iFulLWidth + 'px';
	oHeader.onmouseover = function () {
		ddMenu(1);
	}
	oHeader.onmouseout = function () {
		ddMenu(-1);
	}
	oHeader.innerHTML = 'Parcye Portal Navigation';
	

	var oNav = document.createElement("dd");
	oNav.id = 'portalnav_box';
	oNav.style.left = Math.round((iFulLWidth - 800) / 2) + 'px';
	oNav.onmouseover = function () {
		cancelHide('one');
	}
	oNav.onmouseout = function () {
		ddMenu(-1);
	}

	oNav.innerHTML = '<b>Sites</b>';
	
	var oUL = document.createElement("ul");
	oUL.className = 'portalnav_box'; 
	
	oUL.innerHTML = oUL.innerHTML + '<li><a href=""><img src="http://portalnav.parcye.com/images/logo1.jpg" alt="" border="0"></a></li>';
	oUL.innerHTML = oUL.innerHTML + '<li><a href=""><img src="http://portalnav.parcye.com/images/logo2.jpg" alt="" border="0"></a></li>';
	oUL.innerHTML = oUL.innerHTML + '<li><a href=""><img src="http://portalnav.parcye.com/images/logo3.jpg" alt="" border="0"></a></li>';
	oUL.innerHTML = oUL.innerHTML + '<li><a href=""><img src="http://portalnav.parcye.com/images/logo4.jpg" alt="" border="0"></a></li>';
	oUL.innerHTML = oUL.innerHTML + '<li><b>Overige sites</b><br />';
	oUL.innerHTML = oUL.innerHTML + '&raquo; <a href="" class="portalnav_box">Parcye Blog</a><br>';
	oUL.innerHTML = oUL.innerHTML + '&raquo; <a href="" class="portalnav_box">Flickr Sample Site</a><br>';
	oUL.innerHTML = oUL.innerHTML + '&raquo; <a href="" class="portalnav_box">Suits2Fit Maatpakken</a><br>';
	oUL.innerHTML = oUL.innerHTML + '&raquo; <a href="" class="portalnav_box">Todo Tipo Games</a></li>';
	
	oNav.appendChild(oUL);
	
	oDl.appendChild(oNav);
	
	oDl.appendChild(oHeader);
	oDl.appendChild(oNav);
	document.body.appendChild(oDl);
}

var DDSPEED = 10;
var DDTIMER = 15;

// main function to handle the mouse events //
function ddMenu(d)
{
	var h = document.getElementById('portalnav_head');
	var c = document.getElementById('portalnav_box');
	clearInterval(c.timer);
	if(d == 1)
	{
		clearTimeout(h.timer);
		if(c.maxh && c.maxh <= c.offsetHeight)
		{
			return
		}
		else if(!c.maxh)
		{
			c.style.display = 'block';
			c.style.height = 'auto';
			c.maxh = c.offsetHeight;
			c.style.height = '0px';
		}
		c.timer = setInterval(function(){ddSlide(c,1)},DDTIMER);
	} else
	{
		h.timer = setTimeout(function(){ddCollapse(c)},50);
	}
}

// collapse the menu //
function ddCollapse(c){
	c.timer = setInterval(function(){ddSlide(c,-1)},DDTIMER);
}

// cancel the collapse if a user rolls over the dropdown //
function cancelHide(id){
	var h = document.getElementById('portalnav_head');
	var c = document.getElementById('portalnav_box');
	clearTimeout(h.timer);
	clearInterval(c.timer);
	if(c.offsetHeight < c.maxh)
	{
		c.timer = setInterval(function(){ddSlide(c,1)},DDTIMER);
	}
}

// incrementally expand/contract the dropdown and change the opacity //
function ddSlide(c, d)
{
	var currh = c.offsetHeight;
	var dist;
	if(d == 1)
	{
		dist = (Math.round((c.maxh - currh) / DDSPEED));
	} else
	{
		dist = (Math.round(currh / DDSPEED));
	}
	if(dist <= 1 && d == 1)
	{
		dist = 1;
	}
	c.style.height = currh + (dist * d) + 'px';
	c.style.opacity = currh / c.maxh;
	c.style.filter = 'alpha(opacity=' + (currh * 100 / c.maxh) + ')';
	if((currh < 2 && d != 1) || (currh > (c.maxh - 2) && d == 1))
	{
		clearInterval(c.timer);
	}
}