var DDSPEED = 10;
var DDTIMER = 15;

// main function to handle the mouse events //
function ddMenu(id,d, mEvent){
  //var h = document.getElementById(id + '-ddheader');
  //var c = document.getElementById(id + '-ddcontent');
  
  var dropdown = findAncestor(mEvent.target, 'DL');//FireFox
  if (dropdown == null)
	dropdown = findAncestor(mEvent.srcElement, 'DL'); //IE
  
  var h = findChildElement(dropdown, id + '-ddheader');
  var c =  findChildElement(dropdown, id + '-ddcontent');
 
 // alert('content:' + c.nodeName + ', content parent:' + c.parentNode.nodeName + ' ~ header:' + h.nodeName + ', header parent:' + h.parentNode.nodeName);
  
  
  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);
  }
}

function findChildElement(parent, id){
	var children = parent.childNodes;
	var i;
	for(i=0; i< children.length; i++){
		
		var child = children[i];
		if(child.id == id)
			return child;
	}
	return null;
}

function findAncestor(child, name){
	
	var theParentNode = child.parentNode; //Firefox
	
	if (theParentNode == null)
		theParentNode = child.parentElement; //IE
		
	if (theParentNode.nodeName == name)
		return theParentNode;
	else
		if (theParentNode.nodeName != 'HTML')
			return findAncestor(theParentNode, name);
}

// 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, mEvent){
  //var h = document.getElementById(id + '-ddheader');
  //var c = document.getElementById(id + '-ddcontent');
  
  var dropdown = findAncestor(mEvent.target, 'DL');//FireFox
  if (dropdown == null)
	dropdown = findAncestor(mEvent.srcElement, 'DL'); //IE
  
  var h = findChildElement(dropdown, id + '-ddheader');
  var c =  findChildElement(dropdown, id + '-ddcontent');
  
  
  //alert('content:' + c.nodeName + ', content parent:' + c.parentNode.nodeName + ' ~ header:' + h.nodeName + ', header parent:' + h.parentNode.nodeName);
  
  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);
  }
}