var DDSPEED = 6;
var DDTIMER = 15;

var slide = false;
var lastDT;

// main function to handle the mouse events //
function ddMenu(DT)
{	
	var DD = DT.nextSibling;
	
	while(DD.tagName != 'DD')
		DD = DD.nextSibling;

	clearInterval(DD.timer);
	
	if(slide == true && lastDT != DT)
		ddMenu(lastDT)
	if(slide == false)
	{
		clearTimeout(DT.timer);
		if(DD.maxh && DD.maxh <= DD.offsetHeight)
			return;
		else if(!DD.maxh)
		{
			DD.style.display = 'block';
			DD.style.height = 'auto';
			DD.maxh = DD.offsetHeight;
			DD.style.height = '0px';
		}
		DD.timer = setInterval(function(){ddSlide(DD,1)},DDTIMER);
	}
	else
		DT.timer = setTimeout(function(){ddCollapse(DD)},50);
		
	slide = !slide;
	lastDT = DT;
}


// 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(id + '-ddheader');
	var c = document.getElementById(id + '-ddcontent');
	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);
}