var DDSPEED = 10;
var DDTIMER = 15;
var DDFINALOPACITY = 90; //100 is fully opaque

// main function to handle the mouse events //
function ddMenu(id,d){
  var h = document.getElementById(id + '-ddheader');
  var c = document.getElementById(id + '-ddcontent');
  c.style.width = '200px';  
  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 - 1;
	  c.style.width = '200px';
    }
    c.timer = setInterval(function(){ddSlide(c,1)},DDTIMER);
  }
  else
  	{ h.timer = setTimeout(function(){ddCollapse(c)},150); }
}

// 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 * DDFINALOPACITY / c.maxh) + ')';
  //It is done expanding and contracting
  if(currh < DDSPEED)
  {
	  c.style.opacity = 0;
	  c.style.filter = 'alpha(opacity=0)'; 
  }
  if(currh < DDSPEED && d != 1)
  {
	  clearInterval(c.timer);
  }
  
  if((currh < 2 && d != 1) || (currh > (c.maxh - 2) && d == 1))
  	{ clearInterval(c.timer); }
}