var DDSPEED = 5;
var DDTIMER = 15;

// main function to handle the mouse events //
function ddMenu(id,d){
	var h = document.getElementById(id + 'Button');
	var c = document.getElementById(id + 'Navigation');
	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(id + 'Button');
	var c = document.getElementById(id + 'Navigation');
	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);
	}
}

function hideElements(target) {
	document.getElementById(target).style.display = "none";
}