var DDSPEED = 8;
var DDTIMER = 1;

// main function to handle the mouse events //
function ddMenu(id,d) {		
	var h = document.getElementById(id + '-ddheader');
  	var c = document.getElementById(id + '-ddcontent');
 	
  	if (d == 1)
	{
    		h.style.background = '';
    		
  	} else {
		h.style.background = '';
  	}
	if (c)
	{
		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 + '-ddheader');
  var c = document.getElementById(id + '-ddcontent');
  
  h.style.background = '';
  
  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);
  }
}